import pygame
pygame.init()
width = 500
height = 500
info = pygame.display.Info()
screen_width = info.current_w
screen_height = info.current_h
window = pygame.display.set_mode((width, height), pygame.RESIZABLE)
fullscreen = True
while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            quit()
        elif event.type == pygame.VIDEORESIZE:
            window = pygame.display.set_mode((screen_width, screen_height), pygame.FULLSCREEN)
            fullscreen = True
        keys = pygame.key.get_pressed()
        if keys[pygame.K_ESCAPE]:
            window = pygame.display.set_mode((width, height), pygame.RESIZABLE)
            fullscreen = False
    window.fill((255, 255, 255))
    pygame.display.update()