An optical illusion is an image that tricks the viewer's mind by distorting or changing what is seen. Optical illusions do not actually deceive the eye itself, but rather trick the brain by manipulating light and shadows in a way that the brain interprets differently than reality. Famous artist M.C. Escher was renowned for his optical illusion artworks, often utilizing simple geometric shapes like circles that he manipulated in impossible ways to confuse the viewer's perception.