This reminds me of a "web site" (remember those) I used to visit a lot years ago, trying to understand Neural Networks and genetic algorithms:

http://www.ai-junkie.com/ann/evolved/nnt1.html

This is old. Perhaps late 90s or early 00. The top domain still uses Flash. But the same OCR example is used to teach the concept. For some reason, that site made it all click for me.