Optical Illusions

Via Stewart Cowan's great Real Street blog, I came across this illusion from the Daily Mail:

I love illusions and thought they cannot be the same.  I covered up the squares with pieces of paper and my hands and was still convinced they were different shades of grey.  However I cut out the squares from the image using Macromedia Fireworks and this is what I got:

Amazing isn't it?  If you don't believe me, try it yourself.

Don't always believe what your brain is telling you.