Cut a paper plate in half and cut the rim off one of the halves. Cut the rim exactly in half.
Lay one piece above the other, as shown in the photograph. Does one piece look bigger than the other? Now switch the pieces and see which one looks bigger. Surprised?
What could cause this effect? Think of your own best answer before you read the explanation below.
How It Works
The top piece looks smaller, no matter which one is on top. Instead of comparing the sizes of the whole pieces, your eyes and brain compare the two curved edges that are closest to each other.
