import pygame

pygame.init()

screen = pygame.display.set_mode((640, 480))
pygame.display.set_caption("Circle Sizes")

BG     = ( 15,  15,  40)
RED    = (220,  60,  60)
GREEN  = ( 60, 200,  80)
YELLOW = (240, 200,  40)

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

    screen.fill(BG)
    pygame.draw.circle(screen, RED,    (120, 240), 30)
    pygame.draw.circle(screen, GREEN,  (320, 240), 70)
    pygame.draw.circle(screen, YELLOW, (540, 240), 110)
    pygame.display.flip()

pygame.quit()