10 CLEAR SCREEN
   11 PRINT AT21,10:"■■■■■■■■■■■"
   12 WAIT 1
   20 LET TEXT$="ABC"
   21 DEF MOVE
   22   PRINT ATY,15:TEXT$
   23   !WAIT 1
   24   PRINT ATY,15:"   "
   25 END DEF 
   26 DO 
   30   LET Y=20
   35   DO 
   60     CALL MOVE
   65     LET Y=Y-1
   70   LOOP UNTILY=0
   72   LET Y=1
   75   DO 
   80     LET Y=Y+1
   90     CALL MOVE
  100   LOOP UNTILY=19
  110 LOOP