10 REM Spirograph
   20 C1=2
   30 C2=-7
   40 R1=10
   50 R2=7
   60 GRAPH 
   70 GLCURSOR (108,-108)
   80 SORGN 
   90 Q=ABS C1
  100 R=ABS C2
  110 IF Q<R LET S=Q:Q=R:R=S
  120 IF R=0 GOTO 170
  130 S=R
  140 R=Q-R*INT (Q/R)
  150 Q=S
  160 IF R<>0 GOTO 130
  170 C1=C1/Q
  180 C2=C2/Q
  190 R=100/(ABS R1+ABS R2)
  200 R1=R1*R
  210 R2=R2*R
  220 C=ABS C1: IF ABS C2>C LET C=ABS C2
  230 R=ABS R1: IF ABS R2>R LET R=ABS R2
  240 N=INT (C*R/2)
  250 M=N/360
  260 L=9
  270 FOR S=0 TO N
  280 A=S/M
  290 A1=C1*A
  300 A2=C2*A
  310 X1=SIN A1*R1
  320 Y1=COS A1*R1
  330 X2=SIN A2*R2
  340 Y2=COS A2*R2
  350 LINE -(X1+X2,Y1+Y2),L
  360 L=0
  370 NEXT S
  380 GLCURSOR (-108,-108)
  390 SORGN 
  400 TEXT 
  410 LF 3