import pygame

pygame.init()
window = pygame.display.set_mode([800,580])

X = 200
Y = 200
speedX = 1
speedY = 1

clock = pygame.time.Clock()

while True:
    window.fill((255,255,255))

    pygame.draw.polygon(
    window,
    (255, 0, 0),
    ((100,100),(300,100),(300,300))
    )

    for event in pygame.event.get():

      if event.type == pygame.KEYDOWN:
        if event.key == pygame.K_LEFT:
          speedX = -1

        if event.key == pygame.K_RIGHT:
          speedX = 1

      if event.type == pygame.KEYUP:
        if (event.key == pygame.K_LEFT or event.key == pygame.K_RIGHT):
            speedX = 0

    pygame.display.update()
    clock.tick(60)