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