Lilac chaser

[1] 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.

[3] The chaser effect results from the phi phenomenon illusion, combined with an afterimage effect in which an opposite color, or complementary color – green – appears when each lilac spot disappears (if the discs were blue, one would see yellow), and Troxler's fading of the lilac discs.

On noticing the moving green-disc afterimage, he adjusted foreground and background colors, number of discs, and timing to optimize the effect.

[citation needed] In 2005 Hinton blurred the discs, allowing them to disappear when a viewer looks steadily at the central cross.

The lilac chaser illusion combines three simple, well-known effects, as described, for example, by Bertamini.