import pygame
import sys

pygame.init()

displaysurface = pygame.display.set_mode((300, 300))

screen = pygame.display.set_mode((400, 300))
background = pygame.Surface((400,300))

surface = pygame.Surface ((10, 10))
surface.fill ((0, 255 ,0))

pos = [175, 125]

while True:
    events = pygame.event.get()
    for event in events:
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_RIGHT:
                pos[0] += 20
    pygame.display.update()

    screen.blit(background, (0, 0))
    screen.blit(surface, pos)
    pygame.display.update()