python 4

import pygame, time, random

pygame.init()

black = (0,0,0)
white = (255, 255, 255)
green = (0, 255, 0)
blue = (0, 0, 255)

dis_width = 600
dis_height = 400

dis = pygame.display.set_mode((dis_width, dis_height))

game_over = False

x1 = 300
y1 = 300

x1_change = 0
y1_change = 0
clock = pygame.time.Clock()

while not game_over:
  for event in pygame.event.get():
    if event.type==pygame.QUIT:
      game_over = True
    if event.type == pygame.KEYDOWN:
      if event.key == pygame.K_LEFT:
        x1_change = -10
        y1_change = 0
      elif event.key == pygame.K_RIGHT:
        x1_change = 10
        y1_change = 0
      elif event.key == pygame.K_UP:
        x1_change = 0
        y1_change = -10
      elif event.key == pygame.K_DOWN:
        x1_change = 0
        y1_change = 10
  if x1 >= dis_width or x1 < 0 or y1 >= dis_height or y1 < 0:
    game_over = True

  x1 += x1_change
  y1 += y1_change
  dis.fill(black)
  pygame.draw.rect(dis, white, [x1, y1, 10, 10])
  pygame.display.update()
  clock.tick(10)

pygame.quit()
quit()