w = 640 : h = 480
graphsize w, h

dim k = {black, red, green, blue, purple, cyan, yellow, white}
h /= 4

for i = 1 to 4
    col = 0
    y = (i-1) * h
    for x = 1 to w step i
        if col mod 8 = 0 then col = 0
        colour k[col]
        rect (x, y, x + i, y + h)
        col += 1
    next x
next i