David Friedman of Ironic Sans has always enjoyed stereograms, which you might know as Magic Eye images. They were quite the fad in the 1990s, but existed long before that and are still being generated today. Friedman gives us the history of stereograms and plenty of examples of experimental computer-generated stereograms that you've probably never seen. The above stereogram was created by Scott Pakin. Friedman describes it:
All that stuff is neat and clever. But there’s one Scott Pakin stereogram in particular that really brings a smile to my face because it plays not just with depth perception, but with how our brains perceive color, and it feels more like magic than any other stereogram I’ve ever seen.
You'll see examples of stereograms in history, advertising, video, and art in Friedman's newsletter devoted to the subject. -via Damn Interesting
(Image credit: Scott Pakin)