10 CLS
20 SCREEN 5
30 c=0
40 x=0
50 y=0
60 xs=SCREEN.WIDTH/16
70 ys=SCREEN.HEIGHT/16
80 INK CLUT("VGA",c)
90 RECT FILL x,y,x+xs-1,y+ys-1
100 INK RGB(0,0,0)
110 RECT x,y,x+xs,y+ys
120 c=c+1:IF c>=256 THEN END
130 x=x+xs
140 IF x>=16*xs THEN x=0:y=y+ys
150 GOTO 80
