smoking clover

smoking clover n.  [ITS] A {display hack} originally due
   to Bill Gosper.  Many convergent lines are drawn on a color monitor
   in {AOS} mode (so 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.