I really like the figure showing the nearest-neighbour graph of MNIST being stretched as it goes through the hidden sigmoid layer. Really helps build an intuition for those of us who think visually or geometrically.

He quotes Bret Victor at the end:

"When Hamming says there could be unthinkable thoughts, we have to take that as “Yes, but we build tools that adapt these unthinkable thoughts to the way that our minds work and allow us to think these thoughts that were previously unthinkable.”"

Great work!