A simple diagram replicating the effect I'm sure you've all seen from time to time with circles moving linearly along a line to form the illusion of a rotating circle.
Cartridge code (161 chars):
o=64m=16s=sin ::l:: cls() for i=0,m do g=i/m line(o,o,o+s(g)*60,64-cos(g)*60,7) ⧗=t()/3+g x=s(⧗)*s(g)*60 y=s(⧗)*cos(g)*60 circfill(o+x,o-y,3,8) end flip() goto l
