import pygame
import sys
import random

pygame.init()
 
sc = pygame.display.set_mode((500, 500))

m = 0
x = 10
k = 1
direct = 1
y = 0
while 1:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit()
    
    pygame.draw.rect(sc, (255, 255, 255), (x,y,1, 1))
    print(x)
    if x < 250 and direct == 1:
        y = x 
        x = x + 1
    else:
        direct = 2
    if direct == 2:
        y = y - 1
        x = x + 1
    pygame.time.delay(5)
    pygame.display.update()