[pygame] Moire pattern in arc and circle

[Paul Vincent Craven]

I get moire patterns when I draw arcs, circles and such if the
line-width is thick. Here's an example:

import pygame
pygame.init()

screen=pygame.display.set_mode([500,500])

#Colors
blue=[0,0,255]
green=[0,255,0]
screen.fill (blue)

pygame.draw.circle(screen,yellow,[100,100],50,50)
pygame.display.flip()

done=False
while done==False:
    for event in pygame.event.get():
        if event.type==pygame.QUIT:
            done=True