The lilac chaser is a visual illusion, also known as the Pac-Man illusion. It consists of 12 lilac (or pink, rose, or magenta), blurred discs arranged in a circle (like the numbers on a clock), around a small black, central cross on a grey background. One of the discs disappears briefly (for about 0.1 seconds), then the next (about 0.125 seconds later), and the next, and so on, in a clockwise direction. When one stares at the cross for about 5 seconds or so, one sees three different things: