   10REM>mouse-doodle
   20MODE 13
   30OFF
   40GCOL0,RND(63)
   50T%=0
   60REPEAT
   70MOUSE X%, Y%, B%
   80IF B% = 7 THEN ON:END
   90IF B% = 6 THEN CLS: GOTO 70
  100IF (B% AND 4) OR T%=1 THEN DRAW X%,Y% ELSE MOVE X%,Y%
  110IF B% AND 1 THEN GCOL0,RND(63)
  120IF B% = 2 THEN T%=T% EOR 1: REPEAT: MOUSE A, B, C: UNTIL C=0
  130WAIT 1
  140UNTIL 0
