100 GR 
  110 DIM tgs(2)
  120 tgs(2) = 15
  130 tgs(0) = 0
  140 DIM spots(GWIDTH, GHEIGHT)
  150 mx = GWIDTH * GHEIGHT * 0.95
  160 FOR x = 0 TO GWIDTH - 1 CYCLE 
  170   FOR y = 0 TO GHEIGHT - 1 CYCLE 
  180     spots(x, y) = 0
  190   REPEAT 
  200 REPEAT 
  210 //
  220 i = 0
  230 dir = 1
  240 target = tgs(dir + 1)
  250 CYCLE 
  260   x = RND (GWIDTH)
  270   y = RND (GHEIGHT)
  280   z = spots(x, y)
  290   IF z <> tgs(dir + 1) THEN 
  300     z = z + dir
  310     spots(x, y) = z
  320     COLOUR = z
  330     PLOT (x, y)
  340   ENDIF 
  350   IF (i MOD 1000) = 0 THEN 
  360     WAIT (0)
  370     IF FN count(target) THEN 
  380       dir = dir * -1
  390       target = tgs(dir + 1)
  400     ENDIF 
  410   ENDIF 
  420   i = i + 1
  430 REPEAT 
  440 END 
  450 //
  460 DEF FN count(target)
  470 LOCAL x, y, c
  480 c = 0
  490 FOR x = 0 TO GWIDTH CYCLE 
  500   FOR y = 0 TO GHEIGHT CYCLE 
  510     IF spots(x, y) = target THEN c = c + 1
  520   REPEAT 
  530 REPEAT 
  540 IF c > mx THEN 
  550    = TRUE
  560 ELSE 
  570    = FALSE
  580 ENDIF