Biliárdgolyó

import pygame

pygame.init()

screen = pygame.display.set_mode((600, 400))

pygame.display.set_caption("Pygame Sample")

clock = pygame.time.Clock()

x, y, dx, dy, r = 300, 200, 4, 3, 24

running = True

while running:

    for event in pygame.event.get():

        if event.type == pygame.QUIT:

            running = False

    x += dx

    y += dy

    if x - r < 0 or x + r > 600: dx = -dx

    if y - r < 0 or y + r > 400: dy = -dy

    screen.fill((20, 24, 40))

    pygame.draw.circle(screen, (233, 30, 99), (x, y), r)

    pygame.display.flip()

    clock.tick(60)

pygame.quit()

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