import pygame, sys
from pygame.locals import *

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

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

pos = [175, 125]

pygame.display.set_caption("Hello, World!")
while True:
    for event in pygame.event.get():
        if event.type == QUIT:
            pygame.quit()
            sys.exit()
        if event.type == pygame.KEYDOWN:
            if event.key == pygame.K_RIGHT:
                pos[0] += 20
    DISPLAYSURF.blit(background, (0, 0))
    DISPLAYSURF.blit(surface, pos)
    pygame.display.update()