PROC MAIN()
  CARD I     
  BYTE POINTER SCR ; BEGINNING OF SCREEN POINTER
  CARD POINTER DLADDR ;DISPLAY LIST ADDR
  GRAPHICS(7+16)        
  DLADDR=PEEKC(560)+4  
  SCR=DLADDR^ 
  ; PLOT AN ARBITRARY PATTERN ON SCREEN
  FOR I=1 TO 3840
  DO
   SCR^=135
   SCR==+1
  OD             
  FOR I=1 TO 33000 DO OD
RETURN