https://www.youtube.com/watch?v=XNZIN7Jh3Sg
https://www.youtube.com/watch?v=ogBPFG6qGLM
(Or if you want to put them full-screen on infinite loop in a darkened room: http://www.infinitelooper.com/?v=XNZIN7Jh3Sg&p=n http://www.infinitelooper.com/?v=ogBPFG6qGLM&p=n )
The code for the 1st is available in a Gist linked from its comments; the creator of the 2nd has a few other videos animating grid 'fantasies' of digit-recognition neural-nets.