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I've acquired a new superpower

• soperj 2y ago
  Any recommendations for when you can't get the images to quite overlap? I feel like I can get 75% of the way there, but then they start going the other direction. I can do magic eye easily.
  • kayge 2y ago
    Use your browser to zoom out and make the images slightly smaller
    • soperj 2y ago
      this made all the difference in the world.
• dalemyers 2y ago
  I'm amazed that there's so many comments and yet not a single one is pointing out that the coffee bean is missing from the _right_ side of the image. Not the left.
• calebm 2y ago
  Super cool. It works for me. I love magic eye stuff.
• bambax 2y ago
  It's funny, it really works. Was also able to spot the difference on the coffee beans image: https://i.imgur.com/0TcWvWJ.png https://i.imgur.com/0TcWvWJ.png
• on_the_train 2y ago
  The superpower being writing clickbait titles for trivial posts
• edelbitter 2y ago
  de-clickbaited: to spot minor differences between two images, view them like stereograms
• yegle 2y ago
  I feel old knowing https://en.wikipedia.org/wiki/Magic_Eye https://en.wikipedia.org/wiki/Magic_Eye
• JoeOfTexas 2y ago
  Wife was not impressed. That hit home haha.
• MarkusWandel 2y ago
  Wait, that's not crossing your eyes, it's uncrossing them. Ordinarily if you look at something nearby, your eyes aim at a common spot. But when viewing a stereogram, you need to convince your eyes to aim at a spot more distant than the subject. This is easy with practice, however IMHO it helps to be significantly nearsighted. Then you simply take off your glasses, and can look at something nearby with infinity focus, which is naturally associated with uncrossed eyes. I don't know whether it's possible to train yourself to diverge your gaze, i.e. stereoscopically see images that are separated more than your pupil distance. Certainly I can't do that.
  • semireg 2y ago
    While intuitive, I’m not so sure. I look at the center line and slowly cross my eyes until the 3rd image slides into place and then I get focus lock. At no time do I feel my eyes uncross and go the other way. Hmm!
  • satvikpendem 2y ago
    See my other comment about cross view vs parallel view, looks like you can do one vs the other and the author can do the opposite.
    • vault 2y ago
      Wow. Thanks to MarkusWandel I discovered I can focus images while crossing my eyes and finally understood your comment. I've always done the "uncrossing" since I was a kid.
  • teddyh 2y ago
    Both work equally well if you just want to spot differences. Cross-eyed view is somewhat easier to do, since people naturally cross their eyes when looking at something close to their face, but there is no natural reason for one’s eyes to diverge. But cross-eyed view also gives a subjectively smaller image, and is also not the usual way autostereograms are made to be seen.
    • 2y ago
• satvikpendem 2y ago
  Note that there is a difference between crossview and parallel view. See this image [0] and try to overlap them. Depending on what you see in the foreground, that is the type of view you're able to see. Basically, it determines whether the 3D view you're seeing from the stereoscopic pair is convex (pops out of the page) or concave (goes into the page). It is of course possible to learn both views but most people naturally see one or the other. You can go to r/crossview or r/parallelview depending on which one you see. [0] https://i.redd.it/g5ilwgk99r781.jpg https://i.redd.it/g5ilwgk99r781.jpg
  • alt227 2y ago
    I find that there are different techniques to seeing both. If I stare at the image and cross my eyes until focus lock I get crossview where the image goes back into the page. If I bring the image right up to my eyes and stare through it into the distance, then slowly move the image backwards into my gaze until I get focus lock, then I get parallel view where the image pops out of the page. I have always wondered the difference between the two and why it happens. Thanks for shedding some light on it :) EDIT: I have just managed to achieve both without moving my head or the image for the first time in my life! Just by trying to look further 'past' the picture into the distance, and then by slightly crossing my eyes and focussing at a point in front of the picture. I have been trying to do this for 30 years, and it is only your explanation which helped me to do it. Thanks so much!
    • jasonjmcghee 2y ago
      I had never done the parallel view before either- spent 5 or so minutes at it and finally got it. For me it's still takes a fair amount of effort to maintain it (unlike cross view that takes effort to stop seeing it instead) but the 3d looks way more impressive somehow. Like the Toronto crowd one- hadn't seen so much depth in a "magic eye" before
      • wruza 2y ago
        I believe it’s better because it is more natural to eyes. You may also want to play with the perspective. E.g. the hall here looks much better from 0.4m than up close on my phone due to the picture’s perspective. https://triaxes.com/docs/3DTheory-en/522ParallelCrosseyedviewingmetho.html https://triaxes.com/docs/3DTheory-en/522ParallelCrosseyedvie...
• dreadlordbone 2y ago
  For some reason when attempting this my neck starts cramping
• a1o 2y ago
  A new way of doing git diff, leave both versions of the code side by side and cross your eyes.
  • louiechristie 2y ago
    My thoughts exactly. Could be done with a git diff in a VR headset
    • xattt 2y ago
      If you’re already spending the computing effort to create the VR image… /s
  • justahuman74 2y ago
    I sure didn't expect there to be a plausibly work-related angle when I came to this thread
  • bicx 2y ago
    New business idea: git diff, but it uses Mechanical Turk to hire an army of cross-eyed diff spotters.
    • waffletower 2y ago
      There is a wonderful stable diffusion prompt here.
    • deleted 2y ago
      [deleted]
  • satvikpendem 2y ago
    Somewhat related, but I've been using the Semantic Diff extension in VSCode, works better than standard git diff.
    • deleted 2y ago
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• etaioinshrdlu 2y ago
  Who's been doing this since they were maybe 7 years old :)
• Damogran6 2y ago
  I was really good at the random dot stereograms. This is a really cool recasting of that skillset.
  • alt227 2y ago
    I think thats the best part of this skill. Everyone did 'Magic Eye' images as a kid, but to be able to take that useless skill and apply it to something more useful and interesting is really cool.
• ChrisMarshallNY 2y ago
  Dammit! I can't uncross, now! https://www.youtube.com/watch?v=qaz2hxZLycY https://www.youtube.com/watch?v=qaz2hxZLycY
• Fauntleroy 2y ago
  I'm not sure this works if you have astigmatism
  • mikepurvis 2y ago
    I did until it was corrected with LASIK a year ago, and I could still do magic eyes, both with and and without my glasses on.
  • ehayes 2y ago
    I have a small astigmatism (and wear glasses) and I was able to do it, but I feel like if I did any more today I'd have a headache.
  • EvanAnderson 2y ago
    Having similar acuity in both eyes made a huge difference for me. I'm somewhat astigmatic but was able to do this eye "uncrossing" trick just fine. I had a significant loss of acuity in one eye and that's what left me unable to do this (or to watch 3D movies).
• OscarCunningham 2y ago
  This is called 'vdiff' in the Jargon File: https://jargonfile.johnswitzerland.com/vdiff.html https://jargonfile.johnswitzerland.com/vdiff.html
• erwincoumans 2y ago
  That's fun, it worked for me as well. I could spot the difference in all images, including the 'impossible mode'.
• etaioinshrdlu 2y ago
  Who's been doing this since they we're maybe 7 years old :)
  • tobr 2y ago
    Checking in! I’m frequently baffled by how unaware most people seem to be about the absolute basics of how their eyes work. Like, people don’t even seem to be aware of how their stereo perception is largely made from two images, or any of the implications that has. I actively think about the two images maybe dozens of times per day.
    • graypegg 2y ago
      Chill out, that's a bit of hyperbole isn't it? This is just a trick for doing a spot the difference puzzle. It's not exactly a daily task most people are thinking about. Most people at least understand that stereographic vision has something to do with 3D perception because we've all closed 1 eye before.
      • tobr 2y ago
        It’s a useful way to compare visual things, which comes up in all kinds of contexts other than these puzzles.
  • jeffbee 2y ago
    I figured everyone because I had a puzzle book that instructed readers to do this.
    • knallfrosch 2y ago
      We've had these stereoscopic books with hidden images and I never saw any. So I've been failing at this since 7 years old – does that count?
  • lowdest 2y ago
    Yup I used to do this with tile floors as a child.
• ThrowawayTestr 2y ago
  Neat. If this isn't working for you, try on mobile. It's easier if the images are small.
  • dreadlordbone 2y ago
    This helped, thanks.
  • rufus_foreman 2y ago
    You can also just back away from the screen. For the 3rd one I had to back up about 6 feet from my monitor before it clicked into place, once it is in focus you can move closer to see the difference better.
• ktzar 2y ago
  I used to use that trick with some arcade game that was popular in bars in 00s Spain. People were just impressed!
• FL410 2y ago
  Very cool. Even the impossible mode one was relatively easy!
• tunnuz 2y ago
  That's so cool, thanks for sharing this. I managed to do all of them, in the impossible one I identified correctly the area, but couldn't pinpoint the difference.
• voidUpdate 2y ago
  I've heard about this before, but I've never actually managed to do it until just now. I needed to sort of "tune the parameters" a lot so that my eyes were crossed but also focused, since I've had a lot of trouble actually getting them in focus when I'm doing it, and the effect isn't as pronounced as I expected it to be
  • idiotsecant 2y ago
    I think you're still not doing it quite right. The effect is really quite obvious and pronounced.
    • piva00 2y ago
      It took me some attempts but I agree, it's very obvious, the 2nd image made it glaringly obvious after I managed it well on the 1st one. My eyes get very watery after just a few seconds though, curious to hear from others how common this side-effect is.
• SysComp 2y ago
  Not working for me
• rstarast 2y ago
  that's why they mirror one of the images in "find the differences" in puzzle competitions, e.g. USPC https://wpc.puzzles.com/uspc2024/ https://wpc.puzzles.com/uspc2024/
  • schlauerfox 2y ago
    reminds me of convolution operation.
• doctoboggan 2y ago
  I've been doing this since I was a kid as well. When I was younger some restaurants would have video monitors with games on them, and one of them was spot the difference. I essentially maxed out the score and still held the highest score when I came back in town years later. I wonder if its still around...
• deleted 2y ago
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• TonyTrapp 2y ago
  Doesn't work for me. Just like stereograms. I just don't know how to "tell" my eyes to cross. Maybe similar to how I didn't figure out until I was 20-something how finger snipping works. Maybe by the time I'm 50 I can cross my eyes...!
  • dgacmu 2y ago
    To do it with crossed-eye view, try looking at your finger and slowly moving the finger closer to your eyes until you see a third image come into view in between the two on the screen. At some point your brain will/might let you focus on that image.
  • alt227 2y ago
    You dont 'tell' your eyes to cross, you just look closer or further away. Try looking at the image at normal distance, whilst imaginging that you are looking into the distance at a beautiful view or at the horizon on an ocean. It is this difference in distance focusing which causes the illusion.
    • s3krit 2y ago
      Actually, given enough practice, you can literally just get your eyes to do it. I started doing magic eye puzzles as a kid and loved it, so just eventually learned how to control my eyes in that way. Even today, if I see any repeating pattern, or even anything vaguely similarly shaped, I can’t help but do it
      • jeffhuys 2y ago
        When they snap together it feels soo good…
    • Karawebnetwork 2y ago
      Whenever I try to do this, the most I get is that the two images touch. The cats in the example are holding paws, but they never overlap. I've been trying to make this work since the old magic images from the 90s, but I've never managed it. I wonder if there isn a hardware limitation related to my eye configuration.
• the__alchemist 2y ago
  If you've done Magic Eyes, this is straightforward. Was able to get all 3 of the test images quickly. This is with focusing beyond the screen. Focusing in front of the screen is something I am unable to do, and not for want of effort. Also, your eyes might accidentally do this if looking at tiled patterns, e.g. wallpaper. Relative image size (e.g. view distance) is important.
  • mikepurvis 2y ago
    I have a slightly lazy right eye, so this has always come naturally to me, but I will say it's considerably easier to achieve the false focal lock on printed material— something about screens, even quality ones with high refresh rates, just isn't the same.
  • johnthedebs 2y ago
    As a kid, I got a Magic Eye book and learned to see it by crossing my eyes (ie, focusing in front of the screen). I thought it was pretty interesting when I realized that I was seeing all the images inverted ("peaks" were "valleys" and vice versa) due to the way I was focusing. Alas, I never was able to see the images "correctly".
    • ses1984 2y ago
      Instead of crossing your eyes to focus in front of the image, you have to uncross them and focus on something behind the image. Put your finger about six inches in front of your face and then look at the horizon. If the horizon is in focus you should see two fingers.
      • whatshisface 2y ago
        Focusing behind is much easier because you can get yourself started by focusing on an actual object.
        • aidenn0 2y ago
          Focusing in front can be done by focusing on an actual object too? Many people e.g. put a finger between them and the picture and then remove it.
• whywhywhywhy 2y ago
  This same technique can be used for a 3D effect: https://old.reddit.com/r/CrossView/ https://old.reddit.com/r/CrossView/
• not_a_bot_4sho 2y ago
  Every Asshole knows this trick for targeting spacecraft https://youtu.be/XGdjKvivJA8?si=lRrfl6rHzAsE7nEO https://youtu.be/XGdjKvivJA8?si=lRrfl6rHzAsE7nEO
• robofanatic 2y ago
  Thanks! now I have a migraine
• chrisbrandow 2y ago
  Every 80’s kid knows this trick from those old books where you cross your eyes to reveal images.
• tobr 2y ago
  More things you can use this for: ”Are these two things the same size?” ”Are these things that are supposed to be evenly spaced actually evenly spaced?” ”Are all these things straight/at the same angle?” ”Is the wallpaper pattern aligned everywhere?” ”Is that surface using a repeating texture?”
  • dredmorbius 2y ago
    I may originally have stumbled across this trick looking at repetitive patterns. I distinctly recall automobile upholstery (with a regular recurring ventilation pattern). In particular, abberations in the pattern (dirt, missed holes, etc.) stood out. Similarly, acoustic ceiling tiles, repeating patterns on wallpaper, rugs, or draperies, building faces, etc. This may be a superpower to some, or a supertorment to those with OCD ;-)
• Jzush 2y ago
  I didn't know this had a name or was considered a skill. I've done this since the 90's when those magic eye books became popular. I even managed "impossible mode" in 2 or 3 seconds.
• Workaccount2 2y ago
  At a local bar they had a game machine, and if you got a high score on any of the games, your tab for the evening was free. One of the games was a "spot the differences" between two pictures with an ever decreasing timer for each round. Using this trick I was able to easily surpass the high score, and garner a crowd watching me perform this mind numbing feat. Probably my peak fame right there.
  • throwaway743 2y ago
    Just got a funny visual of someone going crosseyed and focused on overcoming a challenge in front of them, with a crowd of people cheering them on.
  • deleted 2y ago
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  • soco 2y ago
    I can't overlap the images to save my life - they get like halfway there and that's it...
    • waffletower 2y ago
      That happened to me too but I persisted and eventually succeeded. I think I needed to cross my eyes slightly more than I was initially. I have been diagnosed with a minor eye convergence issue which makes it difficult to focus on near field objects in motion -- gaining this superpower was difficult but I did it without a headache thankfully.
    • ThrowawayTestr 2y ago
      Try on mobile, it's easier if the images are smaller.
      • pivo 2y ago
        Wow, yeah it happened immediately for me on mobile while I couldn't get past half way on my monitor. Thanks!
• deleted 2y ago
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• codazoda 2y ago
  Weird timing. I dunno why this works but I've been using it to see mice. You see, I noticed that I have a mouse problem in my garage. I figure if I've seen one mouse, there are probably more. So, I stood on some stairs in my garage and crossed my eyes to sort of blur the scene. It allowed me to catch movement more quickly and I was quickly watching multiple mice run around the edges of the area.
  • idiotsecant 2y ago
    That seems like not the same thing though, right? You're not doing a diff on two images, you're just losing resolution so you can direct more attention to movement.
    • thunderbong 2y ago
      I think it's because our peripheral vision is able to observe movements faster.
  • mncharity 2y ago
    Hmm. I noticed in lectures, if I stilled my eyes, most of the field of view would grey out, except for areas of motion (eg a lecturer's head or writing arm) which appeared normal. After motion stopped in an area, it would slowly grey out. When a motion started, its area would snap to normal, making it easy to spot onsets of motion. Eventually my eyes would twitch, and the whole field would refresh.
    • iamjackg 2y ago
      I've done this in the past with bugs in the grass. If I stare at a fixed point, I start seeing each individual bug moving through the grass, whereas normally they would be really hard to spot among all the fine details of the ground and grass blades.
    • athom 2y ago
      I first read about this back in the 1980s, in an issue of Science Digest. Couldn't find a link or reference on short notice, but here's something from the American Academy of Ophthalmology that explains the phenomenon, with an experiment to see the blood vessels in your eye: https://www.aao.org/eye-health/tips-prevention/experiment-see-blood-vessels-in-your-eye https://www.aao.org/eye-health/tips-prevention/experiment-se... Apparently, the brain tends to ignore visual stimuli that don't change over a short period of time, which allows you see "around" the blood vessels passing through the middle of your eye. By closing your eye, and moving a penlight around against your eyelid, you can make the vessels cast a shifting shadow on your retina that makes them visible. The reason you usually see everything out in front of you is that various actions cause your eye to shift about just a little, just enough to cause the image on your retina to shift about enough for the brain to notice.
• egypturnash 2y ago
  You can also now free-view stereo image pairs. Congratulations.
• robotguy 2y ago
  When auto stereograms were all the rage in the late 80's I had a program on my Mac Plus that let me make/edit them and I used to edit for hours WHILE looking at them in 3D. Then one time I was walking down a hallway with a repetitive wallpaper pattern, my eyes did the thing, the entire hallway appeared to shift in front of me, and I stumbled and fell. Still to this day my eyes will sometimes automatically snap into 'alternate' focus when viewing a repetitive pattern.
  • shaftway 2y ago
    This happens to me too. Particularly when it's on a narrow horizontal repetition (like wooden slats on a wall). I attribute mine to playing a lot of the game Magic Carpet from the mid to late 90's. It had some interesting graphics modes, including Red/Blue anaglyph 3D and a stereogram 3D mode. It was fun to try to play it, but it used noise for the pattern, so you didn't get textures, only blobby shapes.
  • wruza 2y ago
    This happens to me easily inside cars with these dotted-breathing roof interior patterns. (Edit: g “perforated vinyl fabric”) Well, worse than easily - sometimes I cannot get back to normal and am not sure how far it actually is, because the nature of the pattern allows to re-lock at every few cm. I just don’t know where I’m really looking at unless there’s an irregular object nearby.
    • floydnoel 2y ago
      I don’t share a lot of comments from HN with my spouse, but this made me crack up so much that I just had to. Thanks for the story!
  • xamuel 2y ago
    No need for the Mac Plus program, you can make these in any text editor. Use a fixed-width font and fill a line with a repeating word eg WORDWORDWORDWORDWORDWORDWORDWORDWORDWORDWORDWORDWORD Then copy that and paste it a bunch of times to make it multi-line. Cross your eyes so that the WORD's overlap (all except the leftmost and rightmost). You now see two cursors instead of one. Position your two cursors anywhere you want and then insert a space in order to make the corresponding WORD (or ORDW or RDWO or ORDW) sink into the screen. (Or rise if you parallel-view.) We used to do this in the computer labs back in 6th grade.
• nayuki 2y ago
  I discovered this trick independently about a decade ago, to use cross-eyed viewing to easily spot differences between two similar images. Like you said, the parts that mismatch appear to shimmer and be unstable, making them obvious. However, I feel eye strain from doing it, so I prefer other methods. 99% of the time, I do https://en.wikipedia.org/wiki/Blink_comparator https://en.wikipedia.org/wiki/Blink_comparator instead, just switching between two images with zero flicker and zero displacement offset. Also with both eyes, it's easier to spot certain kinds of subtle differences like color shifts, JPEG-like compression artifacts, tiny differences in antialiased renderings, etc. One benefit of the cross-eyed method, though, is that you can difference videos. But the use case for that is rarer than differencing images.
  • jeffhuys 2y ago
    To reduce eye strain, don’t cross your eyes, but relax them (so, the other way). Instantly clear and snaps together as if magnetic.
    • tartoran 2y ago
      The problem I have with this is that instead of the images completely overlapping they overlap a section in the middle. I can't get both images to completely overlap and am getting some eye strain from trying to force them.
    • claiir 2y ago
      This is called “divergence” [1] and is less straining on your eyes than crossing them (“convergence” [2]) while being equally as effective spotting differences, even on video. It’s also what your eyes naturally do when you watch stereoscopic 3D with tinted glasses—the stereoscopic images are pulled out (divergence) not pushed in (convergence/cross-eyed). I’ve been doing this since I childhood. If you get good at it, you can watch side-by-side 3D videos in 3D with just your naked eye (e.g. VR). I believe there’s a reddit covering the more prurient variety of that! [1] https://en.wikipedia.org/wiki/Vergence#Divergence https://en.wikipedia.org/wiki/Vergence#Divergence [2] https://en.wikipedia.org/wiki/Vergence#Convergence https://en.wikipedia.org/wiki/Vergence#Convergence
• anarticle 2y ago
  Incredible! This technique is also used for the 3d visualization of protein structures, it was called "cross viewing": https://imgur.com/cross-views-are-commonly-used-to-view-protein-structures-3d-UR69BKY https://imgur.com/cross-views-are-commonly-used-to-view-prot... You cross your eyes to get the two images to line up, hold it there and then try to adjust the focus of your eyes. It's a neat skill to have.
  • meatmanek 2y ago
    I found the toolbars and stuff around the edge of the image made it difficult for me to lock onto the crossview image in your example; surrounding it with more blank background makes it easier for me: https://imgur.com/a/NizzRgo https://imgur.com/a/NizzRgo
• dogman1050 2y ago
  The stars puzzle helped me find a speck of dirt on my phone screen.
  • dylan604 2y ago
    The funny thing about the stars image is this is a common way to find asteroids, comets. It's not limited to just those. Only instead of a bunch of cross eyed astronomers, they overlay and align the images and do subtraction/difference filtering to see what's left. For comets/asteroids, the dot of interest will move between frames. Even just playing back the aligned images as a timelapse can reveal motion.
  • dredmorbius 2y ago
    Also handy for identifying dead pixels!
• norswap 2y ago
  Wow that's interesting — trying to cross my eyes produces hellish jitter. I suspect it's because my left eye is slighty lazy. But I was able to superimpose the right cat picture onto the left one (it's a lot harder for the more complex sky resort picture). It's pretty eerie, the right picture just slides right up the left one (I did need to figure out the right distance for it). It doesn't help me pick out the differences though, I mostly only see the right picture, and if try to focus my left eye, the right picture slides out. Still, intersting.
• xkcd-sucks 2y ago
  Autostereogramming it doesn't help me lol If it's perfect, the overlapping regions just merge in color, i.e. the cat's paw becomes off-white. If it's not perfect, I still have to attend to which parts are popping in and out. In both cases I still have to compare the merged view to the left and right hand sides. Although it is very nice for illustrating each eye's contributions to the merged view. Just not an attention-saver.
• evan_ 2y ago
  I use this technique to get web layouts pixel-perfect with the mockup, just put both windows next to one another and superimpose them with your eyes. Works great. There are tools that do this by overlaying an image with 50% alpha but it doesn't work as well. Last year when there was a bunch of fuss about Kate Middleton not having made any public appearances there was a minor flap where people claimed that a photo she'd released was just an edit of an earlier photo. There was a tweet presenting two photos, one old and one purporting to be new, where she was holding strikingly similar poses. The claim was that the new one was just an edit of the older one. I used this technique and immediately the minor differences stuck out like a sore thumb- her hand was rotated more in one, her hair was laid differently, etc.
• klik99 2y ago
  I picked this up during the magic eye craze of the 90s, and I will never not find it hilarious how people get shocked at my ability to find the differences. I always share the skill too, it’s one of those things people find impossible until they get it and it’s easy.
• twolf910616 2y ago
  dang it i just did this on a zoom meeting. hopefully no one saw me trying to cross my eyes
• TheRealPomax 2y ago
  This is how I help my family when they're stuck on "spot the difference" steam games. It also takes literally any fun out of them, the actual game has to come from not (just) spotting differences, because that task is trivial.
• comonoid 2y ago
  I knew some people who used it to compare aerial photos (though generally a special device with mirrors was used).
  • hk__2 2y ago
    > though generally a special device with mirrors was used Maybe this: https://en.wikipedia.org/wiki/Blink_comparator https://en.wikipedia.org/wiki/Blink_comparator
    • comonoid 2y ago
      No, a modification of this: https://en.wikipedia.org/wiki/Stereoscope https://en.wikipedia.org/wiki/Stereoscope
• 7bit 2y ago
  I've done this on these game machines 30 years ago when I was 10. I'm baffled that there are still people who have to figure this out.
• jogu 2y ago
  I remember doing this as a child on our TV that had a picture-in-picture setting. I would set the same channel twice and cross my eyes pretending that it was 3d TV.
  • dylan604 2y ago
    How does that work when the two images are different sizes and overlapping? Did your PiP mode have a split screen option? The ones I've seen only allowed moving where the insert was placed (which corner), but it was always a PiP and never a split screen.
    • jogu 2y ago
      Yes, it had a split screen option where the two images were the same size and side by side. Can't recall what kind of TV it was... perhaps a Sony?
• timthorn 2y ago
  This is effectively how Pluto was discovered (not cross-eyed, but with a tool to help): https://airandspace.si.edu/stories/editorial/finding-pluto-blink-comparator https://airandspace.si.edu/stories/editorial/finding-pluto-b...
• f0e4c2f7 2y ago
  Front page of HN. Funny to imagine thousands of people sitting in the office crossing their eyes at their computer screen right now.
  • Fnoord 2y ago
    All it did was hurt my eyes. I'll opt out of playing, superpower be damned.
    • haswell 2y ago
      I think the key is not "going cross-eyed" as much as it is relaxing your focus until the images merge. If you intentionally cross your eyes, it hurts. If you de-focus/relax your eyes until the images merge, it doesn't hurt.
      • HaZeust 2y ago
        Relaxing focus for me doesn't cause merging or cross-eyed effects, it causes my vision to go too blurry to do anything lol
        • boogieknite 2y ago
          i had the same thing where best i could get when i relaxed was a narrow merge, and when i crossed my focus was too close to my face to be helpful, plus strain. sudden clicked after fully crossing 5 or 6 times and then relaxing and was able to hold the "3rd image" very easily. felt like magic, even hardest difficulty was obvious
          • Fnoord 2y ago
            For me it just does not work right now. Maybe I have bad eyesight, I wear glasses and am past 40. I believe I was able to do this trick in past though. At the very least on psychedelics (various kinds). This also made me able to relax my eyes more, wheras I normally have too much pressure on them according to optician.
• llm_trw 2y ago
  I've used this to quickly read through a few hundred page documents given to us only as a scanned pdf which was too low quality to run ocr (at the time) on. The sleazy counter party was very upset when I came back with notes on them not adding the changes we asked for on the drafts they sent back within minutes of them sending them back.
  • layer8 2y ago
    I can’t parse your second sentence.
    • whatshisface 2y ago
      Uncross your eyes! :-) (They're saying that the person who send the contract was trying to trick them, and that they were upset when the trick was caught.)
    • fragmede 2y ago
      a counterparty is the other person you're signing a contract with who sometimes lies to you and says they changed things when they didn't
      • layer8 2y ago
        It was the grammar I had trouble with, not the vocabulary. A comma before “within” would have helped a bit.
    • deleted 2y ago
      [deleted]
  • zupa-hu 2y ago
    Oh wow you can also use this for contract diffing when signing in person!
• foobarian 2y ago
  It's a sailboat!
  • kayge 2y ago
    Hah, Kevin Smith caught some flak for that one: " Someone called out Kevin Smith for this on one of his podcasts. According to Smith, on the day of filming, he asked if the picture really was a sailboat, and the prop master said no. When Smith started questioning this, the prop master said that a) it flashes on the screen too quickly for anyone in the theatre to notice, and b) VHS was too low-resolution for people to freeze-frame it to try it at home. So Smith let it slide. Smith summed up, "Now, thanks to Blu-Ray, I get people pointing this out to me all the time!" " https://www.reddit.com/r/MovieDetails/comments/9lf52b/in_the_movie_mallrats_the_magic_eye_poster_was/ https://www.reddit.com/r/MovieDetails/comments/9lf52b/in_the...
• j3s 2y ago
  all i managed to do was make myself very dizzy
• intalentive 2y ago
  Validates a claim in the predictive processing paradigm. The diff between actual and expected is what matters to error correction. That's where all the relevant information is.
• valbaca 2y ago
  Learned this at a young age with the Highlights magazines at the dentist.
• freecodyx 2y ago
  I used to play this game with a friend when we were at the pub, once we start struggling spotting the differences we know we’re drunk
• alfiedotwtf 2y ago
  This is also how I used to do Magic Eye images when I was a kid. Although the stereoscopic image was inverted on the z axis, it was a lot easier than to cross eyes by looking further out into the distance
• unkulunkulu 2y ago
  Hah, old trick, I read pull requests this way for years
• throw7 2y ago
  I always feel like I'll permanently see cross eyed if I keep doing that. It doesn't help that I was accidentally hit in the head by my double's partner racket in tennis and spent like a minute or two walking around seeing double. Not fun.
• belowm 2y ago
  After a short period of training, I got to the point where I can see the third image which I can focus on. However, the differences are very subtile and don't stick out at all :/
  • drdo 2y ago
    Try the second test image (the one labelled "Hard", with the snow). That one was far easier for me than the first (the cat one).
    • belowm 2y ago
      Indeed, that did the trick. Thanks!
• breadsniffer 2y ago
  Wow. That’s insane! With the trick I can somehow solve them all!
• deleted 2y ago
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• error404x 2y ago
  I tried crossing my eyes, but it’s not working for me; I keep seeing things blurry. Maybe I’m doing it wrong. However, I solved the first two puzzles. For the last one, I just guessed randomly. My guess wasn’t exactly correct, but it was close, just a little distance away.
  • bootwoot 2y ago
    One thing I noticed: because you're tricking your eyes into thinking they're observing at a different distance, your brain doesn't seem to correctly account for head tilt (my theory of the diagnosis). Anyway, I think you're head must be exactly level with the image or you'll get double-vision/blur
  • sdwvit 2y ago
    It’s way trickier if you have astigmatism
• evandrofisico 2y ago
  Come on, I've been doing this since I was like 4 years old, this can't be news for anyone, Am i right???
  • jeffhuys 2y ago
    Yes, I didn’t think people would be so amazed by it either. Like it’s mind-blowing that this works or has been thought of. But we first did it once as well, some people just discover it late in life I guess (or not at all).
• manishfoodtechs 2y ago
  I can overlap. But still need to match overlap with anyone.anyway interesting
• jasperry 2y ago
  Claims have been made (outside the medical mainstream) that regularly practicing crossing your eyes helps stave off presbyopia. One does get better at seeing stereograms with practice, so it seems like it at least improves some type of muscle control.
  • svilen_dobrev 2y ago
    uh dunno. 25y ago, i was working behind a 30" tube monitor (a ~35kg hog), with 1 inch thick frontglass.. and one day, one of my eyes started to focus on the (closer)outside of the glass, the other on the (farther)inside of the glass. Could not shake that with closing/blinking. Worse, later, when i got into the car, the closer eye focused on the windshield - instead on the landscape ahead. Took 1 week of everyday 1-2 hours staring far away at the ocean, to revive. AND removal of the monitor :/
  • jredwards 2y ago
    Okay, but my eyes hurt now.
• nullbyte 2y ago
  My Piano teacher used to have this book on her coffee table with images like this. You could blur and cross your eyes, and the image would combine to become 3D. But I never knew this technique could be used to spot the difference between images. Very cool discovery!
• deleted 2y ago
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• ayeeyeiiieee 2y ago
  ITT: everyone telling us their stories about how great they are at stereograms. We get it, you're all super special.
• rererereferred 2y ago
  This is a game mechanic in one of the trials in Ace Attorney Chronicles.
• woah 2y ago
  Do people not know about this?
• kiwiguy1 2y ago
  This is the coolest thing I have seen on here!!
• cyberax 2y ago
  This trick had been used in practice to detect fake banknotes and coins, with a device like a two-sided periscope. It allowed a bank worker to put a real coin on one side and the tested sample on the other, so that any differences can be immediately apparent.
• iforgotpassword 2y ago
  We got a magic eye book when I was maybe 6 - some time early elementary school. After learning how to do it, and also trying it by crossing my eyes to see an "inverted" image, I started doing it whenever I saw some repeating pattern IRL. It was most interesting when it was slightly uneven, for example a fence with sloppily applied vertical planks. Doing the magic eye would make it seem like some of them are closer to you than others. Eventually I tried the same on those "spot the difference" games since well it seemed kinda obvious to try, and I was blown away that it accidentally gave me that "superpower". I think that was pretty smart for a 6yo. Has only gone downhill ever since. ;-)
  • xamuel 2y ago
    I wrote a paper about doing this using human eyes as the "repeating pattern" (either someone else's, or your own in a mirror): https://philpapers.org/archive/ALEDSK.pdf https://philpapers.org/archive/ALEDSK.pdf ...You can use this trick to make boring meetings or conversations mildly more amusing (but be careful not to look like a clown crossing your eyes). If you're an expert at this, you can even do it to your own hands. Hold both hands in front of you but with one of them palm-away and one of them palm-toward you, so that they have the same shape, then cross- or parallel-view them to get an illusionary middle third hand. Walk around while focusing on the third hand and it's a seriously trippy effect. Another "super power" application similar to OP: the ability to confirm whether or not two distant digital clocks' seconds-digits are perfectly in sync. Since they're distant, it takes time to shift one's gaze from one to the other, making it hard to confirm whether they're in sync. But cross your eyes so as to reduce the distance, and voila. Yet another application: quickly assume the same head-tilt angle as your conversation partner. Suppose they tilt their head to the left by N degrees and you want to tilt yours the same way, how can you be sure you have the exact correct tilt? Easy: parallel-view their eyes (as described in the aforementioned paper). You will HAVE to tilt your head the same as them in order to see their "third eye" (and once you've locked on to their third eye, you can effortlessly adjust your head tilt as they do by using their third eye as the necessary guide)
    • mensetmanusman 2y ago
      Peak HN. Stereogramming your colleagues eyes during boring meetings. Ha Edit: I accidentally did something similar by imaging the crease on an N95 mask as a smile near their nose. It made them look like ducks and I had to bite my tongue so hard to not laugh. I could not unsee it.
• brailsafe 2y ago
  Damn, it works exactly that well.
• seanssel 2y ago
  I’ve tried this in the past without luck, but suddenly I can do it now after reading about the subtle “shimmer” effect. Very cool!
• deleted 2y ago
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• svilen_dobrev 2y ago
  half-off-topic.. i have ~1 diopter shortsightness. Was less before, slowly going up. So screens are getting blurrier. Have glasses but still try avoid using them. If i put the (flat edged) TV remote control at about 10cm from my face so it horizontally shadows lower half of both eyes, i see perfectly (without any glasses). go figure..
• HaZeust 2y ago
  It works for me like every tenth time I cross my eyes to look at a "spot the difference" picture. I don't know how it works for people instantly.
• lxe 2y ago
  Instead of crossing your eyes and attempting to focus, what can really help relax your ocular muscles is to do the opposite: look "past" the images into the distance until the images overlap.
• adamc 2y ago
  I couldn't do the cross-eyed thing, but it took me maybe 20 seconds to spot the difference just by looking at sections of the images. But I'm not sure that would have worked had the missing bean been buried in the denser part of the photo.
• AlexandrB 2y ago
  Some repeating tile patterns like stripes will cause my eyes to do this automatically and it's really weird and annoying because everything else gets blurry. Fun trick though.
• StevenNunez 2y ago
  Jokes on you, my eyes don't work together so I can only see out of one at a time!
  • ibeff 2y ago
    There's dozens of us!
  • mewpmewp2 2y ago
    Jokes on me - because I learned that today that this is not normal. Now I wonder what other people see...
• claiir 2y ago
  An alternative technique called “divergence” [1] (pulling your eyes apart) is significantly less straining on your eyes than crossing them (“convergence” [2]) while being equally as effective spotting differences, even on video. It’s also what your eyes naturally do when you watch stereoscopic 3D with tinted glasses—the stereoscopic images are pulled out (divergence) not pushed in (convergence/cross-eyed). I’ve been doing this since I childhood. If you get good at it, you can watch side-by-side 3D videos in 3D with just your naked eye (e.g. VR)! I believe there’s a reddit covering the more prurient variety of that. [1] https://en.wikipedia.org/wiki/Vergence#Divergence https://en.wikipedia.org/wiki/Vergence#Divergence [2] https://en.wikipedia.org/wiki/Vergence#Convergence https://en.wikipedia.org/wiki/Vergence#Convergence
  • iamjackg 2y ago
    This is what I do, the only issue is that I don't have nearly as much "range" with divergence as I do with convergence, so I have to make the pictures as small as possible when using it to line up two images (as opposed to autostereograms, which usually have a much smaller divergence offset).
  • sirobg 2y ago
    Do you have a training method for divergence? Similar to the finger moving closer and closer to the upper nose technique, for convergence.
    • Pxtl 2y ago
      It's a little more abstract since you don't have handy moving-reference-object like your finger, but: Place the picture in front of something deep, like a long hallway. Look off at something in the distance behind the picture, like the end of the hallway. Notice how the edge of the picture is a double image. Focus on gradually resolving the edge of the picture down from double-image to single-image, and then do the reverse by looking down the hallway again and seeing the picture go back into double-vision. Just keep practicing that until you get the feel for controlling your depth perception and then try holding the same depth of the hallway while you turn your gaze to the picture and try the same action with your eyes.
• dathmar 2y ago
  I was hoping to get a new superpower today, but when I was young I was cross eyed. I got this corrected through surgery and can no longer cross my eyes.
• blipvert 2y ago
  “Impossible mode” was the easiest for me - took a few seconds. Probably due to the aspect ratio and the size of the images on my phone screen.
• mannykannot 2y ago
  This did not work for me. I was able to invoke a middle image, but there was no shimmering. After I found the difference the old-fashioned way, I realized that the middle image showed the distinguishing feature as it is on my non-dominant side.
• nixpulvis 2y ago
  I can produce the third image by crossing my eyes, but one eye dominates and all I see is a cat with three stripes on its head. :(
• bluedino 2y ago
  I have been doing this forever, if you get the high score over a certain threshold you can get a free game (400,000?) I would usually get accused of memorizing all the pictures. You will get bored or a headache before you stop getting free games using this technique. You can get stifled by the older machines with faded CRT screens. The newer LCD (that's how old these games are...) are usually better to play on.
• tarunkotia 2y ago
  Image worked but when I tried with text it did not work. Is there some trick to it?
• marnett 2y ago
  Woah that is amazing how quickly I was able to apply this. So cool!
• CrimsonCape 2y ago
  I have a true vision-based super power. my vision is so bad with nearsightedness that when I take corrective lenses off, I can focus on an ipad mini screen within 10" of my face and perceptually it is the same as focusing on a distant movie theater screen. No straining, eyes totally relaxed. With the lights off, it's better than being in a theater. I tried an ipad pro in the Apple store and it felt like I had my own personal unfairly huge IMAX screen.
  • computerdork 2y ago
    I have really bad vision too (my prescription is left: -8.00, right: -7.50). Tried this out, and yeah, really works! And realized, you need the best resolution screen possible, because you can see every detail. Not sure how much I'll use this is the future, but good to know it's always an option!
  • boxed 2y ago
    Natures own VR goggles.
  • dsubburam 2y ago
    Unlike when focusing on a movie screen, your eyes have to turn inward to direct the pupils to converge at the physically near iPad. This can cause muscular eye strain (it does for me). You can get clever and order a prismatic prescription that bends light out, so your eyes don't have to turn inward. I tried it too, but it gave me nausea.
• uoaei 2y ago
  I appreciate the sentiment but "overlay the images by crossing your eyes" receiving that kind of incredulous reaction is really funny and kind of sad for me. I hope it's just amateur editorializing.
• deleted 2y ago
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• kevinsync 2y ago
  I've got -7.5 myopia/nearsightedness in both eyes, with astigmatism. As a result, my eyes can easily go out of focus to do Magic Eye or this type of thing. The bonus superpower is, if I take my contacts out and get really close up on something, it's like I'm looking through a microscope; if I happen to have glasses on, sometimes I can also catch the light and focus in just the right way to further magnify what I'm seeing already zoomed in. In those instances I see whatever's reflecting through the glasses, so mostly eyelashes and skin/pores, but it's fascinating nonetheless. Can't see a damn thing beyond the tip of my nose without corrective lenses though LOL
  • drumttocs8 2y ago
    Same vision, and I found it hard to do at first- but super cool when the image appeared crystal clear!
• hyperthesis 2y ago
  A parallel processor is you!
• hn_throwaway_99 2y ago
  There are some great examples and detailed explanations IMO of this general phenomenon in the book "How the Mind Works" by Stephen Pinker. It essentially discusses how your brain is doing statistical work to build the 3D model from these 2 stereoscopic images.
• null0pointer 2y ago
  You can use this same technique to view glasses-less 3D (stereoscopic) images. It's also fairly easy to create your own. Take two photos but offset the camera lens by approximately eye-width. Open the image editor of your choice and place the images side-by-side. View the composite image cross-eyed and you are now viewing a 3D scene. Also worth noting there are 2 versions of this kind of cross-eyed focus depending on whether your eyes are focusing on a point in front of or behind the actual image. This determines which side the left and right eye images should go on in the composite. I find it easier to focus on a point in front of the images but IME most examples online are for focusing on a point behind the image.
• thwg 2y ago
  Please stop using that RSS icon on your "Subscribe" button if you don't intend to provide an RSS feed.
• sirobg 2y ago
  This is incredible! Works unbelievably well. Thanks for sharing!
• kazinator 2y ago
  I found it almost instantly, which was by dumb luck. But in the following few moments, seeing two nearly identical photos side by side soon made me think of stereograms, since I'm into them, and have shot a few in my lifetime. I then used my eyes to overlap the images. In binocular overlapped view, the difference loudly draws attention to itself, because it flickers between the two eyes. It's almost as if there were a blinking LED saying "here it is!"
• smusamashah 2y ago
  For anyone who wants to learn this, try this way using your finger as a helper. Put the images in front of your eyes. Bring your finger between your face and the image at almost middle of the distance. Now look at your finger. Move your finger back and forth and notice the background (where your picture is) While doing this, notice that at a particular distance, the images in background will perfectly overlap each other. That's your moment. Pull out your finger and look at that image. -- It worked on everyone I have tried to teach. You may always need help of your finger or a tip of a pencil or whatever. But it's lot easier to get those images to merge this way.
  • skeaker 2y ago
    My eyes seem to immediately refocus as soon as my finger moves away no matter how many times I try this. Before I move my finger away, everything in my peripheral vision is too blurry to be useful.
  • nhumrich 2y ago
    Does this only work on desktop? I am trying this on mobile and the images never overlap. Wondering if maybe my viewport is too smal
  • rahimnathwani 2y ago
    I've always been able to merge pictures by focusing into the distance, and I thought that's how everyone did it. So I found confusing all the talk of crossing eyes. I tried your instructions and, within 30 seconds, was able to see the cat image by crossing my eyes. The cross eyed method seems more amenable to different image sizes. With my regular method, I can't merge images if they're too large (unless I step back).
• dusted 2y ago
  I that not the entire point with those "find the difference" pictures? To teach kids how to do just this ?
• sneak 2y ago
  I was able to do it for the first time after reading this webpage with the technique, cool!
• mjal 2y ago
  Nice to see someone discover this! I've always been partial to spot the differences and crossview images - I am able to cross each eye independently of one another, which makes overlapping these sorts of images very easy. For example, I could cross my right eye, while my left stays perfectly still. This causes instant double vision, and relaxing how crossed the eye is lets me line the images up very quickly. It's fun to do in places with a repetitive wall texture, too - seeing something in real life while adding a faux 3D effect on top of it is kind of trippy. Probably my most useless skill, but a fun one regardless.
• deleted 2y ago
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• theginger 2y ago
  Is the technique to this exactly the same as the technique to view a 3d stereogram image? I was able to get a 3rd image to be clearly visible in the middle doing this, on the 2nd image I could definitely seem some spots appear that lead me straight to 3 of them but didn't work for me on the other 2 images.
  • Pxtl 2y ago
    The left-right full-image stereograms... but those are less common than the pattern-based "magic eye" stereograms. Those are the reverse of this - in the linked image and the left-right full-image stereograms, they're done by crossing your eyes to a point closer to your eyes than the original image. The pattern-based "magic eye" stereograms are done by looking through the image to focus on a point deeper into the screen further from your eyes. The latter I think are less painful because they use the more natural depth-perception distances of your eyes instead of using what feels like more unnatural positions, but that might be my bias because I'm a bit farsighted. Maybe they're just more common because they're visually inscrutable at first and so you get the "reveal" of the 3D contour from a single large image instead of two already-visible small ones.
• amingilani 2y ago
  I'm frequently surprised by the amount of seemingly ordinary skills I picked up as a bored child that other people didn't. This was an obvious way to solve those "spot the difference" pictures in magazines. I wonder what skills other people picked up that I didn't. Some recent example of things I shared: + When your belt buckle hangs a little loosely on the front of your pants. You can hook the buckle's prong onto the front button of your pants and it'll stay put. So many people are excited to learn this. + Putting a jacket or any open-front garment on quickly. I saw someone struggling to maneuver their second arm in a tight jacket behind their back. I explained that if they hold their jacket out in front of them, put their hands in the arm holds, and slide their arm in further as they swing it around their body they'll get it on in a moment. It's also more stylish. They were so surprised.
  • xamuel 2y ago
    Ear rumbling: https://www.reddit.com/r/earrumblersassemble/ https://www.reddit.com/r/earrumblersassemble/ Eye shaking: https://old.reddit.com/r/Eyeshakers/ https://old.reddit.com/r/Eyeshakers/ Some of us are born with small frenula of the tongue (or we undergo tongue-tie surgery as kids) and can thus perform Khecari mudra without the traditional self-mutilation used by yoga-masters. https://en.wikipedia.org/wiki/Khecar%C4%AB_mudr%C4%81 https://en.wikipedia.org/wiki/Khecar%C4%AB_mudr%C4%81 This can be useful for cleaning tonsil stones or post-nasal drip, but of course you must do so discretely since people would consider that absolutely disgusting If you want to read out loud for long stretches of time and you hate taking breaks to catch your breath: you can read out loud while inhaling too! (It feels and sounds super weird though so this isn't very useful in practice.) And here's a party trick related to OP's super power. Pick a distant object and cross your eyes so as to see it double, preferably with the two doubles distant from each other (i.e., cross your eyes significantly). Then, alternately switch between staring at the left double, and the right double. If you do it right, it will look like your eyes are moving in a bizarre alien way.
    • emmelaich 2y ago
      Here's mine. Look at a patch of grass and ask someone to spot the ant or bug. It's quite difficult. But, if you let your eyes go out of focus, the ground will suddenly become alive with movement of all sorts of ants bugs and creepy-crawlies.
• altgeek 2y ago
  Stereograms have been used in structural biology publications for many decades now. Google 'stereogram structural biology'
• tristramb 2y ago
  I've been using this to do quick source code diffs for years. I started back on the days of printouts.
• athom 2y ago
  Easily defeated by arranging the images vertically. Or at least, makes it a LITTLE bit harder.
• sota_pop 2y ago
  Wonderful! with your write-up, I was able to “see”.
• pbhjpbhj 2y ago
  I've always thought that ability to unfocus the eyes might be related to mental focus. If you have difficulty staying on topic, or a diagnosis of ADD/ADHD or whatever {I'm not equate these} AND find it really hard to do magic eye images... Then please take part in my 'totally scientific study'TM.
  • pbhjpbhj 2y ago
    Upvotes, I agree, I have mental focus issues and can't do magic eye (upvote)
  • pbhjpbhj 2y ago
    Downvotes, I disagree (downvote) {I should have done an actual survey, sorry; felt cute might delete.}
  • pbhjpbhj 2y ago
    I have mental focus problems, magic eye is easy for me. (downvote)
• dabber21 2y ago
  Wait, this is news? that's how I always solved those puzzles, I thought everyone did that
• rahimnathwani 2y ago
  I find it very easy to overlap images, I think because of the eye exercises I had to do as kid. I don't recall what these exercises were for, but there were two: 1. Stare at this image of two incomplete cats, and merge them together into a single complete cat: https://www.google.com/search?q=eye+muscle+cat+card https://www.google.com/search?q=eye+muscle+cat+card 2. This strip of cardboard has a number line on it. Put one end half way down your nose, perpendicular to your face. You will see two lines. Merge them at their furthest point, then merge the next nearest point, repeat. (I think this is called the 'Brock String Exercise', but can't find an image similar to the one I recall.)
• luxuryballs 2y ago
  yep it’s just like those magic eye pictures that were big in the 90s, once you learn how to see those instantly you can do this trick also
• hprotagonist 2y ago
  Good old vdiff: https://catb.org/jargon/html/V/vdiff.html https://catb.org/jargon/html/V/vdiff.html Visual diff. The operation of finding differences between two files by eyeball search. The term optical diff has also been reported, and is sometimes more specifically used for the act of superimposing two nearly identical printouts on one another and holding them up to a light to spot differences. Though this method is poor for detecting omissions in the ‘rear’ file, it can also be used with printouts of graphics, a claim few if any diff programs can make. See diff. An interesting variant of the vdiff technique usable by anyone who has sufficient control over the parallax of their eyeballs (e.g. those who can easily view random-dot stereograms), is to hold up two paper printouts and go cross-eyed to superimpose them. This invokes deep, fast, built-in image comparison wetware (the same machinery responsible for depth perception) and differences stand out almost immediately. This technique is good for finding edits in graphical images, or for comparing an image with a compressed version to spot artifacts.
• JeremyHerrman 2y ago
  To really blow peoples' minds use both hands to tap the differences, keeping the left hand for the left image and the right hand for the right image! From your POV the images are merged so your hands will look like they're tapping a single image, but from the audience's point of view you look like a savant with multi-attention!
• leecarraher 2y ago
  i certainly used this trick back in my college days, prompted by a similar technique for "seeing" 3d stereoscopes on a computer monitor. I feel like i learned it somewhere on Eric Weisstein's Mathworld because the 3d objects viwer app let you split the image into two stereo images. Unfortunately java applets have been banished from the internet landscape.
• Balgair 2y ago
  You can also use this to display 3-D images. You have a stereographic projection of your image (like those kids' view-masters) and then just cross the eyes and look at the middle image. Only since the 2 images are slightly different, you can have the middle image be 3-D. It takes a bit of practice though and causes eye strain (at least for me) It's not a great way of showing the image, but it'll do in a pinch.
• scrozier 2y ago
  I spent weeks doing this, looking at stereoscopic (?) images of protein structures, while a grad student in molecular biophysics. I got so that I could see the overlapped images pretty much instantly. But I'm having a hard time getting it now, even on the easy one.
• javaskrrt 2y ago
  okay, this is so cool. thank you for the new superpower!
• tessellated 2y ago
  That's how I used to help my grandmother when I was a little child. She always used to remark that the last one (5th) was the most difficult to find.
• modzu 2y ago
  and now my eyes are stuck this way forever
• mads_quist 2y ago
  Fuck it does work...
• emh68 2y ago
  Wow! It really works. The missing bean "pops" out at you. The hardest part is getting your brain to focus on the cross-eyed virtual center image.
• grishka 2y ago
  This whole "just cross your eyes" thing has never worked for me, not once. I've seen these strange patterns printed on the backs of notebooks that supposedly make some sort of 3D effect when you "just cross your eyes". Later, when I saw similar images online, I was able to at least visualize these hidden shapes by opening the image in photoshop, duplicating the layer, setting the copy to "difference" and moving it left or right. The regular texture would eventually disappear and the shape would emerge. It's still a mystery to me what it feels like to view these the intended way though.
  • titzer 2y ago
    Here are some tips; 1. When you cross your eyes, gradually let them return to uncrossed. Try to do it as slow as possible. Along the way, try to line up any structures that you see in the image that are repeated from left/right half. 2. Once you are able to hold a cross-eyed gaze long enough with lined up left/right half, slowly move your eyes between different features near the middle. Your eyes will naturally want to start to focus and match up pieces. 3. Don't be too far or too close to the image; they are usually easily viewed from comfortable distances. If the image is too big, make it smaller. It's usually easier smaller. 4. Initially, when you cross your eyes, or look through the image, it will likely be blurry. This is because your brain naturally associates accomodation and convergence with also changing focus. You'll learn to decouple those things and you will more quickly be able to go from focusing on the 2D image to crossing it without changing focus much. There's a whole bunch on this site: https://www.magiceye.com/stwkdisp.htm https://www.magiceye.com/stwkdisp.htm
    • einpoklum 2y ago
      > 1. When you cross your eyes, So, how exactly is that supposed to work? I can manage some de-focusing which makes me see 4 images rather than two. Is that part of it? Otherwise, I don't get it.
      • devvvvvvv 2y ago
        That's exactly it. You have to bring the "copy" of the left side to overlap with the "original" right side. Then move forward/backward until the overlapped 2 come into focus. The shimmering should stick out, was so shocking when it finally clicked for me.
• guico 2y ago
  This is exactly why I read HN
• jon309 2y ago
  This does not work even in the slightest. When I cross my eyes, the image becomes wayyyy too blurry and its hard to keep it in the center for more than a second
• sailfast 2y ago
  This whole time it's been a Magic Eye problem? Geeeeez. This would've won me so many random challenges over the years.
• y-c-o-m-b 2y ago
  Well this is interesting. I was able to find the impossible one within 2 seconds without crossing my eyes. The easy one took about 5 seconds, 3 seconds for hard. I've always been hyper-vigilant with patterns (to a fault), so not sure if that's playing into this. Is that what other folks are experiencing also? I see most comments are trying it with their eyes crossed, but what about without? EDIT: ok I just watched the video. No eyes crossed. For the balloons one I beat out the girl in the video by 2-3 seconds. For the birds about the same. The skittles one tripped me up, couldn't find it. The other few I found around the same time, the lights at the end I didn't find in time either. It seems I'm quicker when there's not too many colors involved. Still that's spooky.
• mmh0000 2y ago
  There's a video game of this called QuickSpot. Back in 2008, this was one of my favorite games for the Nintendo DS. It trains the ability to spot little differences quickly. Sadly, outside of winning a barely known video game, it's not a super useful skill. https://en.wikipedia.org/wiki/QuickSpot https://en.wikipedia.org/wiki/QuickSpot
• ChildOfChaos 2y ago
  I can't seem to do this, it seems impossible for me to cross my eyes. Hmmm.
• lobo_tuerto 2y ago
  This is exactly the same skill needed to see 3d pictures (aka autostereograms).
• s4i 2y ago
  Almost certainly a lot of the people saying they are ”crossing” their eyes are actually ”uncrossing” their eyes; focusing the eyes straighter than what would normally happen on the surface where the image is laid out. This is also how the legendary ”Magic Eye” books were supposed to be viewed. Not by crossing the eyes.
• Imnimo 2y ago
  I can get the overlap to lock in, but the simmering effect is weak and difficult to pick out. Probably still faster than exhaustive search, but I don't feel like I'm at superpower level. Maybe my brain favors one eye more than the other? I know I have different glasses prescriptions for each eye.
  • topspin 2y ago
    It tried just after waking up, using my phone's screen, and it worked immediately. Not exactly a pleasant thing to do, but it does work as described.
• labanimalster 2y ago
  Learned it from Magic Eye books too! But using it for spot-the-difference is way more practical - saves so much time compared to staring at two pictures. Kind of feels like having X-ray vision for finding differences
• abotsis 2y ago
  I have strabismus and have always been good at these games. I wonder if it helps me for similar reasons? The examples on his page were pretty easy for me, though the universe one took maybe 45 seconds.
  • dlgeek 2y ago
    Funny. I also have strabismus and I've never, ever been able to see those hidden picture games or these things even once. I never developed stereoscopic depth perception, which I assume is related.
    • phist_mcgee 2y ago
      Same here, i've always wondered what other people see. An optometrist once said that I see everything as if viewing a tv screen through my eyes, but having no point of reference it looks normal to me. I am pretty bad at parallel parking though, perhaps that's my lack of 'native' depth perception.
      • dlgeek 2y ago
        The Toyota Bird's Eye View/BMW Surround View/etc makes it much, much easier.
    • raggles 2y ago
      yea same boat. I've always wondered what normal depth perception looks like. On the plus side, it is fun to challenge people to wear an eye patch and play table tennis or some other activity and see how bad they are when they haven't developed monocular depth perception cues.
• rahulvarshneya 2y ago
  This is just incredible!
• PUSH_AX 2y ago
  A ton of comments in here saying this is easy/old hat for them. Well I'll be the one to say this blew my mind. somehow creating the third middle image, being able to relax my eyes and even scan around this composite image actually made me giggle out loud on my laptop, a very rare occurrence. Thank you to the author.
• EVa5I7bHFq9mnYK 2y ago
  Using this trick, I wrote a program for 3d plot visualization in the 80-s. It computed two projections of the plot, as if looked by left and right eye, and printed them side to side on the thermal printer. If you looked hard enough, you can bring the two pictures together and see a 3d picture!
• Slow_Hand 2y ago
  This trick is interesting to me as someone who mixes records. I (and mixers in general) have a lot of different tricks for making mono audio objects in the mix feel stereo or have a sense of width or depth. Examples include: 1. Delaying the left or right channel by a few ms (Haas effect). 2. De-tuning one of the channels by a few cents 3. Boosting an EQ band on one channel, with a complimentary cut on the opposite channel. ...and many more. These are usually very subtle changes that our stereoscopic ears have no problem detecting. In any case, when we need to do some forensic searching for possible differences between two near-identical channels we'll invert the polarity on one channel and then sum them. The resulting delta sticks out like a sore thumb and highlights even then tiniest differences between the files. So it's fascinating to discover that we can easily do something similar with our eyes to find the differences.
• simplicio 2y ago
  Feel like people who are old enough to remember that 6 week period in the 90's where those Magic Eye 3d Stereogram pictures were everywhere have a big advantage here.
• shkkmo 2y ago
  I cannot do this by crossing my eyes (focusing on a point between you and the image), I have a hard time getting the cross to stay consistent and it never really "locks in" for me. Instead of crossing my eyes, I unfocus them, effectively look through the image. Once I get the repeating part to overlap cleanly, after a second or two, my pupils adjust their focus and the image fades from blurry to clear in a really satisfying way and kind of "locks in" in a way that takes little to no effort to maintain. With a bit of practice, I can even move my eyes around and look at different parts of the two overlayed images without distrupting the effect at all. I don't know if it's just my brain working differently or if a there is some confusion in the discussion between crossing your eyes and focusing through an item.
• codefoster 2y ago
  I didn't spend the time reading the comments to see if this has been said already, but crossing your eyes works but learning to diverge your eyes is better in some situations. It's easier to learn to cross because you can just look at your nose, and you can bring together two images that are further away by crossing than by diverging. But diverging is the way we are normally (when looking across the room say instead of at a book in front of us) so it's more comfortable.
  • cal85 2y ago
    Interesting, what kind of situations does it come in handy?
• netman21 2y ago
  As a kid I learned to see stereograms in 3D by crossing my eyes. Exact same technique. Comes in handy for Mars images today.
• dionian 2y ago
  I've never been able to 'lock' the two images together like this with my eyes focus. That was incredible.
• GMoromisato 2y ago
  As I understand it, Magic Eye stereoscopic images were originally developed by brain scientists studying how we see in 3D (i.e., how the brain processes 2 eye inputs into a 3D image). There were two competing theories: 1. The brain first does a recognition pass (that's a house, that's a person, etc.) and compares the two eyes to see which objects have moved. 2. The brain compares the two eye inputs first, at the "pixel" level and figures out which pattern of pixels has moved, then afterwards, applies recognition to the resulting 3D image. Magic Eye would only work if #2 is the correct theory (because in Magic Eye, there is nothing to recognize until AFTER you convert to 3D).
• deleted 2y ago
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• TeMPOraL 2y ago
  1. Get a bit closer to the screen so you can see both images clearly. 2. Now, cross your eyes and aim to overlap both images. 3. Draw the rest of the fucking owl. Seriously. Ever since my physics teacher in high school tried to get the class interested in stereograms, everyone and every article I see talking about it treat "crossing your eyes" as an atomic, trivial step. It isn't. I for one have no first clue how to do it, it's not a distinct operation I know how to perform. Perhaps this is because I am nearsighted and wear glasses. Still, I wish articles like these focused on explaining how to do the whole cross-eye thing, because once you master that, everything else becomes instantly self-apparent and doesn't need further explanation (I know because I did manage to accidentally cross my eyes once or twice while looking at a stereogram, so I know how the effect looks like). EDIT: FWIW, I compensate by using another trick for diffing documents with Mark I Eyeball - get them printed on separate pieces of paper, put one on top of the other, and hold in front of you with some bright light behind you (Sun, or your phone's flashlight, will do). Not as good as crossing your eyes, but something I can reliably do.
  • deleted 2y ago
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• z3t4 2y ago
  You can also use this method to watch 3d movies without vr googles.
• srinathkrishna 2y ago
  Wow! That was amazing!
• justinl33 2y ago
  human stereo vision processing has incredibly sophisticated noise filtering capabilities that are still hard to replicate in software. The shimmering effect people report is essentially your visual cortex highlighting areas where the stereo correspondence fails.
• jrmylow 2y ago
  The most mind-bending example of the magic eye effect I've found is people using it in videos. Of course, the internet being what it is, someone made a version of Bad Apple with it: https://www.youtube.com/watch?v=RLuGJGyCS90 https://www.youtube.com/watch?v=RLuGJGyCS90
• rsktaker 2y ago
  That's amazing! Within 40 seconds I overlapped the two hard mode images and saw 8 shimmering objects set within a clear picture. It took me a little longer (maybe a minute), but the two impossible mode pictures snapped together and I saw a single shimmering star within an otherwise crystal clear photograph!
  • k2enemy 2y ago
    You can make the impossible picture (the others too) easier by slightly moving your head back and forth while superimposing the images. The difference will move more than the rest of the image.
• tlhunter 2y ago
  It blows my mind that every human doesn't know this. I figured it out as a child. The easiest way to prevent this is to have one of the two images be slightly tilted. I can rotate my eyes but it's much harder than crossing them.
• deleted 2y ago
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• nneonneo 2y ago
  For whatever reason, it was far easier to do this on my phone than on my laptop, even after trying to fiddle with various combinations of zooming in/out and adjusting my distance to the screen. In some cases, it can also be easier to do without glasses (if you customarily wear them) as it makes the defocusing easier. The effect itself is basically similar to the Magic Eye stereograms (https://en.wikipedia.org/wiki/Magic_Eye https://en.wikipedia.org/wiki/Magic_Eye) which by themselves are pretty neat; your brain can rapidly detect subtle offsets in random patterns to reconstruct depth cues. In the case of “spot the differences”, the shimmering is due to the irreconcilable disparity between left and right images, which manifests visually as a glaringly obvious “unphysical” apparition - e.g. flickering between the left/right images, or appearing to be out-of-plane with the rest of the picture.
  • efskap 2y ago
    The specific term for the shimmering mechanism is https://en.wikipedia.org/wiki/Binocular_rivalry https://en.wikipedia.org/wiki/Binocular_rivalry
• gwd 2y ago
  What's astounding about this is simply the staggering amount of visual processing your brain is capable of doing in parallel.
  • cubefox 2y ago
    Exactly, and it is some form of computing power we normally do not have voluntary access to.
  • netsharc 2y ago
    We know the direction a sound comes from due to milliseconds of difference of the soundwave arriving in one eardrum and then the other...
• donatj 2y ago
  As someone with a lazy eye it's kind of hilarious to me that this isn't common knowledge.
• nepthar 2y ago
  I cannot believe this is unknown to so many people that it's news
  • Ylpertnodi 2y ago
    I cannot believe (well, I can!) that 10,000 by xkcd is unknown to so many people that it's going to be news to them when they look it up.
• TZubiri 2y ago
  This makes my eyes hurt. And it's also not really a usefull life or even primitive skill, just a byproduct of our double eyeballs, which are meant for redundancy and depth measuring. Pass. (Although it was cool to do it once and see the third image in the middle.)
• lazycouchpotato 2y ago
  Fascinating! I was able to grab focus for the first image. Found it hard for the second and third image. I focused on the first one and then scrolled down to the second and third - that made it easier for me.
• scrapcode 2y ago
  Great read. Not sure it was worth being stuck cross-eyed for the evening, though.
• ungut 2y ago
  [dead]
• sans_souse 2y ago
  Would AI not be able to crush this game?
  • gameman144 2y ago
    `memcmp` would be able to crush this game, but the fun is in doing it as a human!
  • phyzome 2y ago
    15 lines of Python would be able to crush this game. But that's not the point.
  • sans_souse 2y ago
    Easy, fellas. . .
• ekTHEN 2y ago
  using the same trick, watch this video: https://www.youtube.com/watch?v=zBa-bCxsZDk https://www.youtube.com/watch?v=zBa-bCxsZDk
• nazgulnarsil 2y ago
  A bunch of math is like this too.
• wexomania 2y ago
  Back when I studied media and communications, around when the first avatar movie created a hype for 3D movies. Me and a couple of friends decided to try and make a 3D movie for class. We made a custom camera rig out of metal brackets and edited the movies cross eyed since we had no actual way of editing in 3D, worked like a charm, altho, it was really hard to get the 3D right.
• astura 2y ago
  As usual, this doesn't work for me because I don't have stereoscopic vision.
• armada651 2y ago
  Am I weird for almost immediately spotting the missing bean as soon as the image showed up? It certainly would've taken me longer to adjust my eyes for the cross-eyed trick. Even the impossible one was harder when trying to use the cross-eyed trick than just visually comparing the two by quickly moving my eyes back and forth.
• panzi 2y ago
  I found two differences in the last picture. Turns out the second was dust on my monitor. XD
• deleted 2y ago
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• qwertox 2y ago
  I've used this method as a diff tool for years. Be it code or product comparison, like CPU specs, or these "spot the difference" images, crossing the eyes can be really useful.
• mcarmichael 2y ago
  Add some trigonometry, and this superpower has historical military applications: https://en.wikipedia.org/wiki/Stereoscopic_rangefinder https://www.youtube.com/watch?v=cbXyAzGtIX8
• gcanyon 2y ago
  I am so remarkably one-eye dominant (my left) that the first image just looks like the right cat to me about 98% of the time. Every once in a bit I'll see the flicker, but even then it's faint and hard to notice.
• devmor 2y ago
  I've been doing this for years and always considered it my secret little hack!
• iDon 2y ago
  I use this for quick comparison of minor differences in code / data (e.g. tables, DNA sequences). Variations in indentation are highlighted also, by standing out of the plane. It's good to hear reports of successful viewing. I've got a 3d / stereogram photo gallery app on the back burner; sounds like a reasonable number of people would be able to view it. There are plenty of guides on how to learn this; some are linked here https://www.reddit.com/r/CrossView/wiki/index/ https://www.reddit.com/r/CrossView/wiki/index/. You-tube used to have support for this; there are still videos tagged yt3d - just regular videos now, not interlaced.
  • fudged71 2y ago
    I wonder if this would be a legitimate form of code diff visualization with VR glasses, just show the A and B for each eye
• ksec 2y ago
  Am I the only one who cant do that? Or does me having aphantasia has anything to do with it?
  • mattigames 2y ago
    It would be pretty weird for aphantasia to have something to do with it, it's pretty much using the same technique one can use for cheap 3D effect with 2 videos from cameras slightly apart, it has everything to do with our bifocal abilities and not much else as far as I can tell.
• Fr0styMatt88 2y ago
  I taught myself how to free-view stereo side-by-side images on my phone but after I did so I found that I would get strong stereo impressions involuntarily just looking at certain repeating patterns in normal circumstances like watching TV with side-by-side images or when looking at patterned wallpaper. My visual system is pretty weird in general so I don’t know how common an experience this is with others. It’s not bothersome at all because I know what it is but it was a little startling the first few times.
• lutusp 2y ago
  Many decades ago, during my time as a NASA Space Shuttle engineer, a co-worker couldn't locate a rogue unbalanced parenthesis in a complex program listing, in the days when computers, instead of identifying a particular syntax error, would print lame error messages like "Something went wrong." Worse, we wrote programs by punching 80-column cards -- no syntax highlighting, no color monitors. My co-worker printed two paper listings, one with the error, one without, and asked me to count parentheses as he was doing, over a dozen pages. But because I knew this "superpower" trick, I laid out pairs of pages and crossed my eyes. A few seconds later I found and circled the error. "Ta-daa!" I said. He never forgave me.
• 14 2y ago
  Yes that top reddit comment is right. Years ago those magic eye pictures came out and at first I struggled to see the 3d pictures. Eventually it became trivial. Then somewhere I noticed it worked really well for those spot the difference puzzles. They often come on kids menus at some restaurants. I could spot all ten differences in seconds and my kids would be amazed. I finally tried to teach them but they found it hard to do. But ya in reality what this girl did was super easy and not challenging in the slightest. When you do it and cross your eyes inwards you cross your eyes until the pictures line up in the middle. The majority of the picture will be clear but any spots that are different will seem blurry. The trick is just not focus on anything in particular and just cross images until they clear up. Then make note of where it seems blurry. Cool trick but definitely ruined spot the difference puzzles for me.
• zoklet-enjoyer 2y ago
  It's a sailboat
• matt3210 2y ago
  Corporate needs you to find the differences between theses two images
• mukunda_johnson 2y ago
  Those kinds of puzzles are part of the CCAT test (annoying test for "cognitive aptitude") and I used this trick.
• ashleyn 2y ago
  my grandmother used to tell me if i went cross-eyed too much, they'd get stuck like that. it took me until a google search at age 15 to see that was an old wives' tale...
• rashidae 2y ago
  Wow, I didn’t know I could do that!! I’m not sure how this new learned trick, can apply to other stuff… but I’m happy I tried it and it did amazed me haha thanks for the share dude!
  • rashidae 2y ago
    1 hour from my tests, my eyes still hurt though!!!
• ribs 2y ago
  What has happened to me? How am I able to create a combined image and have it be -stable-? This totally works. I’ve been mutated.
• User23 2y ago
  I instantly knew as soon as I saw the image. It's the Magic Eye trick. The same one you use to view stereoscopic images. The differences will just flicker.
• nomilk 2y ago
  Amazing! Tiny bit of feedback, it might help to add to the article that there's 1 difference to spot in impossible mode (the other two difficulties say there's 3 and 8 diffs respectively, which is useful to know when attempting).
• ompogUe 2y ago
  Semester 1 when getting a BFA in painting the prof told us to do this to help tighten composition
• econ 2y ago
  Open the image in the Gimp. Duplicate layer adjust opacity then drag it sideways until they line up. Toggle layer visibility..... Wait, why isn't there a service for this? Or is there?
  • pontifier 2y ago
    Set layer mode to "difference" and everything that overlaps exactly fades to black. On a stereo image sliding the top image is very interesting as areas at different distances fade at different positions. Here is an example video I made many years ago with the colors inverted as well for visibility: https://youtu.be/k2-ZZz5rwQE?si=UaKcidDRbNZOftbd https://youtu.be/k2-ZZz5rwQE?si=UaKcidDRbNZOftbd
• dredmorbius 2y ago
  The "impossible mode" example of a starfield is literally how astronomers have found new bodies (planets, asteroids, comets, supernovae, etc.) since the invention of photography. Typically this utilised a negative photographic plate (so that bright objects appeared as dark against a light background making their presence easier to detect for our visual system), and the plates were rapidly flipped. The object which moved or suddenly appeared and disappeared was the new element. This works for nearby moving objects (planets, asteroids, comets) which would track against the stellar background, or distant variable ones (supernovae, variable stars, pulsars) which would appear and disappear (or brighten and fade) over time. Now of course this is automated and direct sensor readings can be interpreted, but the childs' game was at one time Best Scientific Practice. Described here, "How are asteroids discovered?" <https://catalina.lpl.arizona.edu/faq/how-are-asteroids-discovered https://catalina.lpl.arizona.edu/faq/how-are-asteroids-disco...>. There are archives of these astronomical plates, and there are projects which utilise older observations so recorded to make new discoveries even now (or in the recent past). I'd first learned of this visiting the Lick Observatory on Mt. Hamilton near San Jose some years back. Key was that old plates were used to compare current observations using the same 'scope, an otherwise now-archaic instrument but not without its advantages. As I recall, the astronomer doing the study was the same one who'd made the original plates many decades earlier, and was doing this as his own retirement project. There's a description of similar work (including Lick observations) here: "Astronomy's Photographic Glass Plates: Demonstrating Value Through Use Cases" <https://journals.library.ualberta.ca/istl/index.php/istl/article/view/2759/2754 https://journals.library.ualberta.ca/istl/index.php/istl/art...> On plate archives: "Preserving an Astronomical Legacy" <https://skyandtelescope.org/astronomy-news/preserving-an-astronomical-legacy/ https://skyandtelescope.org/astronomy-news/preserving-an-ast...> "APPLAUSE: Archives of Photographic PLates for Astronomical USE" <https://www.plate-archive.org/applause/info/ https://www.plate-archive.org/applause/info/> (dylan604 noted this use case earlier: <https://news.ycombinator.com/item?id=42657956 https://news.ycombinator.com/item?id=42657956>)
• bicepjai 2y ago
  This blog post was nostalgic. Growing up in TamilNadu India, a Tamil weekly magazine called Anandha Vikatan use to have one page of stereogram where an object will be hidden in it. I found it so exciting to do the eye crossing trick to find the image pop up, made me feel great as a kid when my family could not find the image :) fun times
• goose- 2y ago
  What an unexpected and fun read to find on HN. Bonus tip: while focused on the overlapping image in the middle, jiggle your screen, and the diff will move around while the rest remains static. This helped me solve the impossible challenge instantly. I'd love to learn more about the underlying mechanism here. Anyone can point me in the right direction?
• scottshambaugh 2y ago
  This I think is an underrated tool for scientific visualization. I made a matplotlib add-on that will let you make stereogram plots of data, and use this cross eyed or parallel eyed techniques to see it in 3D. https://github.com/scottshambaugh/mpl_stereo https://github.com/scottshambaugh/mpl_stereo
  • notShabu 2y ago
    This is really cool! it allows you to see 2D charts in 3D without actually rendering anything in 3D
  • mkoubaa 2y ago
    Incredible!
• n2j3 2y ago
  The first (easy mode) image worked like magic - I crossed eyes, let them rest and the differences shimmered in a very static 3rd/middle image. Couldn't for the life of me rest my eyes on 2nd and 3rd though. [edit - tried to zoom out, worked on 2nd image too]
• kuon 2y ago
  I have no idea how that is supposed to work. If I cross my eyes I see 3 images and the middle one is a superposition of the two but I don't see any part standing out.
  • throwaway314155 2y ago
    It's subtle. You need to make sure the center image is very well in focus first. Then, the "shimmer" appears but it's not really a shimmer so much as a (fairly mild) perceived depth/edge "artifact". It seems to glow but i think this is more to do with it looking a bit like glowy edge based artifacts from 3d movies w/ 3d glasses.
• Over2Chars 2y ago
  tldr: blogger learns how to cross his eyes for fun and "profit".
• z02d 2y ago
  I recently learned about this from one of my favourite German podcasts: https://freakshow.fm/fs286-zurueck-zur-vision https://freakshow.fm/fs286-zurueck-zur-vision (Starting at 2:50h)
• raffraffraff 2y ago
  Remember the old magic eye posters? Like the static you'd see on an old untuened TV, in monochrome (but some odd colour like puce, cyan or bile) "It's a schooner"
• ninetyninenine 2y ago
  I came into this rolling my eyes thinking he acquired some ability to learn and be humble or some programming or management topic... the typical bs you see on hacker news. Boy was I wrong. This is an actual super power.
• JW_00000 2y ago
  If you can easily cross / unfocus your eyes, it also allows you to see 3D images easily. Try: https://www.reddit.com/r/ParallelView/ https://www.reddit.com/r/ParallelView/ https://www.reddit.com/r/CrossView/ https://www.reddit.com/r/CrossView/
• snvzz 2y ago
  Funny. I crossed my eyes and found the difference before reading the article. Somehow expect most people to know this, but I guess that's not the case.
• nkrisc 2y ago
  Very cool. After a minute I was able to focus on the false “third” image of the overlap of each side, but I couldn’t notice any difference. It did appear to be closer to me than the screen though.
• aiono 2y ago
  When I was little I was doing this on carpet patterns because they suddenly become 3D. It was very fun. But I never realized it could be used for this purpose. There is also one other similar funny ability I have: Vibrating my eyes. I can willingly vibrate my eyes. I don't think it's any useful ability as I just see shaky when I do it but it's fun to do in front of people. It scares some of them. There is actually a community about it in Reddit: https://www.reddit.com/r/Eyeshakers/ https://www.reddit.com/r/Eyeshakers/
• sebastiennight 2y ago
  Thanks to this article I have successfully taken a two-hour break from HN and my computer screen, on behalf of the massive headache I acquired at the same time as the aforementioned superpower.
• keepamovin 2y ago
  Wow so cool! It really just bounces out. I used to love those Magic Eye books. There's something meditative and calming about that sort of focus. This post was really cool!
• 2024user 2y ago
  I can do the 3d images in kids books but cannot make it work for spotting the difference
• jheriko 2y ago
  i didn't use the trick, or read what it was until after i tried for myself. it took me about 7 seconds at a conservative overestimate... then again, i did outperform my entire national cohort at school in almost every subject by a wide margin... an outlier. the trick however is very clever, but it wont work in more complicated scenarios where attention to detail matters. EDIT: after doing the first one near the top i tried the rest. with a bit of warm up its very fast. no tricks needed. maybe a relic of playing these games when younger and having a "once in a generation" level of learning power coupled with training it when very young when learning speed is multiplied by a huge scale factor. i had to zoom the last one, but the other two were incredibly fast, close to immediate. sub second. EDIT2: the warm up was doing the first image once after reading the first few sentences. EDIT3: this is not a superpower.
• pvo50555 2y ago
  I can't believe this has 1587 points (already). Has no one here grown up with those Magic Eye books?
• cassepipe 2y ago
  I've discovered I can't cross my eyes. Any techniques ?
• funnyfoobar 2y ago
  Dumb question: How do I cross my eyes? can someone explain this method in detail?
• ponorin 2y ago
  related: if you have a side-by-side 3d image/video you can do the crosseye to see it in 3D without any special display/glasses. it's just that your eyes are gonna be tired after a movie session.
• menzoic 2y ago
  This is literally a superpower
• menzoic 2y ago
  TIL you can learn super powers on the internet
• pigeons 2y ago
  It just feels like I'm going to harm something if I leave them crossed more than a split second and I stop.
• shw1n 2y ago
  One of the coolest "immediate novelty" things I've read in a while Sent it to my whole family The way your mind locks in and focuses on the middle one seems a testament to the brain processing behind vision we take for granted
• garfieldnate 2y ago
  Doesn't work if you have lazy-eye, unfortunately! I generally just see whatever my stronger eye sees. It might be a good exercise to improve my weaker eye's sight, though.
• yarolig 2y ago
  By the way... There is a nice old good article about making real time stereograms. https://developer.nvidia.com/gpugems/gpugems/part-vi-beyond-triangles/chapter-41-real-time-stereograms https://developer.nvidia.com/gpugems/gpugems/part-vi-beyond-...
• hegzploit 2y ago
  Cool site that I often use with this trick to impress some friends: https://www.spotthedifference.com/practice.asp?m=2&l=4 https://www.spotthedifference.com/practice.asp?m=2&l=4
• ern0 2y ago
  On Amiga, there was a 3D demo with this trick. You can "jump in" your eyes to the proper position if you hold your finger at the place where the 3d image should appear, ca. 10 cm close to your eyes, and focus on it. You'll be cross-eyed without knowing it. Also, I was using the trick as a "cheat" when I played Tiny Lands on Nintendo Switch, it's a "spot the difference" game, but with 3d landscapes (you can rotate and zoom): https://www.dekudeals.com/items/tiny-lands https://www.dekudeals.com/items/tiny-lands
• tenthirtyam 2y ago
  This reminds me of the 4D maze. Let's see if it's still around... yep: https://www.urticator.net/maze/ https://www.urticator.net/maze/ I tried using it, like the author, to visualize and investigate 4D data. But my stone-age brain, regrettably, seems limited to intuiting only 3 dimensions.