import pygame
from pygame.locals import *

pygame.init()
display = pygame.display.set_mode((500, 500))
clock = pygame.time.Clock()
FPS = 60

cnt = 1

while True:
	display.fill((cnt, cnt, cnt))
	cnt = (cnt + 1) % 256
	pygame.display.update()
	clock.tick(FPS)
	for event in pygame.event.get():
		if event.type == QUIT:
			pygame.quit()
			exit()