smoking clover n.
[ITS] A display hack
originally due to Bill Gosper. Many convergent lines are drawn on
a color monitor in such a way that every pixel struck has its
color incremented. The lines all have one endpoint in the middle
of the screen; the other endpoints are spaced one pixel apart
around the perimeter of a large square. The color map is then
repeatedly rotated. This results in a striking, rainbow-hued,
shimmering four-leaf clover. Gosper joked about keeping it hidden
from the FDA (the U.S.'s Food and Drug Administration) lest its
hallucinogenic properties cause it to be banned.