The Ebbinghaus illusion is an optical illusion of relative size perception. In the best-known version of the illusion, two circles of identical size are placed near to each other and one is surrounded by large circles while the other is surrounded by small circles; the first central circle then appears smaller than the second central circle.
do you get it??? the main figures/shapes/whatever are ALL THE SAME SIZE!!!
ps- The Ebbinghaus illusion has played a crucial role in the recent debate over the existence of separate pathways in the brain for perception and action.