10 MODE2 20 FOR N=0 TO 1279 STEP 10 30 GCOL 0,RND(7) 40 MOVE 0,0:DRAW N,1023 50 MOVE 1279,0:DRAW 1279-N,1023 60 MOVE 0,1023:DRAW N,0 70 MOVE 1279,1023:DRAW 1279-N,0 80 NEXT N 90 GOTO10