100 REM Chaos game
110 CLS
120 SCREEN 2
130 X = INT(RND(1) * 256)
140 Y = INT(RND(1) * 192)
150 FOR I=1 TO 20000
160  V = INT(RND(1) * 3) + 1
170  ON V GOTO 180,220,260
180  X = X/2
190  Y = Y/2
200  V = 8 'red
210  GOTO 290
220  X = 128 + (128-X)/2
230  Y = 192 - (192-Y)/2
240  V = 3 'green
250  GOTO 290
260  X = 256 - (256-X)/2
270  Y = Y/2
280  V = 7 'blue
290  PSET(X,Y),V
300 NEXT I
310 END