rem Ring example thanks to Joel Kahn

clg
fastgraphics
rm=0.0
st=0.0251
imx=3.281
imy=3.095
bm=0.2
x=135.0
y=2.0

ring:
rm=rm+st
x=x+imx*cos(rm)
y=y+imy*sin(rm)
q=y*bm
color clear
rect x,y,q,q
color black
ex=x+q
ey=y+q
line x,y,ex,y
line x,y,x,ey
line ex,ey,ex,y
line ex,ey,x,ey
refresh
goto ring