Amman
Look closely at tile A and B. They look like they are different shades of grey. But they are really the exact same shade.
This fantastic illusion was created by Edward Adelson.
Incredibly, both A and B are the same shade of grey. These type of optical illusions usually just use simple contrast to fool the brain, but this illusion employs two effects. First of all, it plays tricks on the mind thanks to the dark shadow contrast around B – but the effect is reinforced by the bright white background contrast near A.
With some ‘training’, it is possible to see both A and B as the same shade, but otherwise you might want to import the picture into a paint package to prove it to yourself
this is interesting, the green thing has an effect as well, so the colors do not match, take it photoshop and check.