DEFINT A-Z SCREEN 12 x0 = 10: y0 = 10: col = 8: w = 50 FOR y = y0 TO y0 + 7 * w STEP w col = 15 - col FOR x = x0 TO x0 + 7 * w STEP w LINE (x, y)-(x + w, y + w), col, BF LINE (x, y)-(x + w, y + w), 15, B col = 15 - col NEXT x NEXT y