After studying this discussion it seems that the puzzle has been solved several more times: There is an active subreddit dedicated to it [1], with a handful of

After studying this discussion it seems that the puzzle has been solved several more times: There is an active subreddit dedicated to it [1], with a handful of people credibly claiming to have solved the puzzle. So "solved for just the third time" is likely not technically true, but the puzzle does seem to be very very difficult. [1] https://www.reddit.com/r/CainsJawbone/ https://www.reddit.com/r/CainsJawbone/ (You can even find a digital version there, but it's not clear if clues have been lost in the digitalisation process).