This optical illusion is a classic example of how our brains can be tricked by our eyes. The Checker Shadow Illusion is a two-dimensional image that appears to be three-dimensional. It consists of a checkerboard pattern with alternating light and dark squares, and a shadow cast across the
From Wikipedia
The checker shadow illusion is an optical illusion published by Edward H. Adelson, professor of vision science at MIT, in 1995. It demonstrates the context-dependent nature of human color perception.