Checker Shadow Illusion.

Saved it, loaded it in photoshop. Same color according to the picker. Yet, my brain cannot see them as the same color. Take a white brush, wipe out the surrounding around the 'lighter' tile. The more you wipe, the darker the tile becomes.

How can anyone trust one's own brain after that.

Yeah, this is one of very few optical illusions that I still can't force myself to see through. Good one.

See how easy it is to fool the human brain? No wonder they're having such a tussle in Kansas over teaching science!

very impressive illusion

i blacked out surrounding squares here - http://i24.photobucket.com/albums/c41/john128/checker-shadow-illusion.jpg

It's easier just to hold your fingers up to the monitor and block everything out except a small part of the two A & B squares. You'll see that they're the same color.

Very tricky illusion there.

See how easy it is to fool the human brain? No wonder they’re having such a tussle in Kansas over teaching science!

Yeah. Some people just can't get over the fact that evolution is not and cannot be proven true. ;o) (how the hey did that topic come up?)

Brilliant - had to test myself before I believed it

Unbelievable! I put it on my blog. Thanks Alex!

dave was that religious babble?

Yes come now Dave. Let's not get into another lame creationism vs evolution debate.