This is sweet.

This is really wacky: http://www-bcs.mit.edu/people/adelson/checkershadow_illusion.html.

If you open the picture up in Photoshop and erase the dark checkers around square B, it slowly starts to look darker. It’s bizarre.

In unrelated news, my quota expires in 15 days, which will surely send me into a spiral of panic and despair.