text: import pygame
  pygame.init()
  
  size = width, height = 640, 240
  speed = [2, 2]
  green = (0, 255, 0)
  
  screen = pygame.display.set_mode(size)
  ball = pygame.image.load("ball.gif")
  ballrect = ball.get_rect()
  
  running = True
  while running:
      for event in pygame.event.get():
          if event.type == pygame.QUIT:
              running = False
          if event.type == pygame.KEYDOWN:
              if event.unicode == 'q':
                  running = False
  
      ballrect = ballrect.move(speed)
      if ballrect.left < 0 or ballrect.right > width:
          speed[0] = -speed[0]
      if ballrect.top < 0 or ballrect.bottom > height:
          speed[1] = -speed[1]
  
      screen.fill(green)
      screen.blit(ball, ballrect)
      pygame.display.flip()