import pygame
import random

pygame.init()

window = pygame.display.set_mode((400, 500))
running = True

while running:
for event in pygame.event.get():

if event.type == pygame.QUIT:
running = False

color = (random.randint(0,255),random.randint(0,255),random.randint(0,255))
window.fill(color)

pygame.display.flip()
pygame.time.delay(1000)