Very disturbing optical illusion

14Dec/093

I really like optical illusions. Until recently, my favorite was this one. But, I have a new favorite now.

Here's one that bothers me. See if it bothers you.

Look at the image below. Which square is darker, A or B, or are they the same color?

A hat tip to John Cook for blogging about this illusion.

Denise
December 15th, 2009 - 07:51

Wow! I don’t think I’ve ever seen a more convincing illusion. No matter how long I stare at it or how much I cover up the rest of the image, I cannot see those squares as the same color.
Rick Regan
December 15th, 2009 - 07:55

What’s even more disturbing is that you can throw away all of the image except a small square encompassing A and B and the illusion STILL exists (I did so here: http://twitpic.com/tmama … feel free to copy it into this comment).

BTW, if you paint a white border around B the illusion disappears.
Bob
December 15th, 2009 - 09:33

Cut or punch a 1/4 inch hole in an index card and hold the hole over the A and then over the B. Look at the card about an inch or so away from the hole so you can take advantage of your peripheral vision.

Wild About Math! Making Math fun and accessible