I know of a site called anomalies unlimited. They have some pretty cool optical illusions. If you do a search it will be the first one on the page...
I love Optical illusions! Honest to gosh Right/Left brain stuff. That one was a basic sepparation. Cool stuff.
gray, darker shade of grey, grey... ow... those things always make sense to me on a theoretical level, but my instincts are always telling me that it cant be
