from PIL import Image
img = Image.new( 'HSV', (600,600))
pixels = img.load()

for x in range(600):
  for y in range(600):
    mathx = x - 300
    mathy = 300 - y
    dist = (mathx*mathx + mathy*mathy)**.5
    pixels[x,y] = (int(dist),255,255)

img.show()