Smoking clover

According to the Jargon File, smoking clover is a computer display hack,[1] originally created by Bill Gosper.

The color map is then repeatedly rotated.

The result of this is a rainbow-hued, shimmering four-leaf clover.

The program has been described as "psychedelic", and Gosper joked about keeping it a secret from the Food and Drug Administration (FDA) due to its "hallucinogenic properties".

Source code for Linux to reproduce the effect is available on the web.