I found the lecture useful. I haven't made it to the end, but there is a good visualization on solving the XOR problem without the Kernel Trick, starting at 26

I found the lecture useful. I haven't made it to the end, but there is a good visualization on solving the XOR problem without the Kernel Trick, starting at 26:57. She shows a multi-layer perceptron and uses two hyperplanes (hidden layer) to write a remapping so that a single hyperplane (output layer) can classify the 4 points. It is a general perceptron example, so it's only one hidden layer, but it shows the gist of DL (transforming data into a new representation) in a way that I hadn't seen before.