Python (using **graphics.py**):

`from graphics import *`

xmax = 800

ymax = 600

win = GraphWin('Circles', xmax, ymax)

win.autoflush = False

win.getMouse()

while 1:

s = 500

for x in range(0, xmax + 1):

for y in range(0, ymax + 1):

a = x * s / 600.0

b = y * s / 600.0

c = a * a + b * b

d = c / 2.0

d = d - int(d)

if d < 0.25:

kol = color_rgb(d * 4, 0, 0)

elif d < 0.5:

kol = color_rgb(0, 2 * d, 0)

elif d < 0.75:

kol = color_rgb(0, 0, 4 / 3.0 * d)

else:

kol = color_rgb(255, 0, 0)

win.plot(x, y, kol)

print x

win.flush()

win.getMouse()

if s == 1000:

s = 500

else:

s += 5