10 GRAPHICS 9:FOR K=1 TO 10 STEP 2:FOR J=0 TO 15:COLOR J:PLOT 0,K*16+J+1:DRAWTO 79,K*16+J+1›20 PLOT 0,K*16-J:DRAWTO 79,K*16-J:NEXT J:NEXT K›30 FOR K=1 TO 255 STEP 16:POKE 712,K:FOR J=1 TO 500:NEXT J:NEXT K:GOTO 30›