import pygame

pygame.init()


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


square_size = 50
num_squares = screen_size[0] // square_size


squares = []
for i in range(num_squares):
    row = []
    for j in range(num_squares):
        square_rect = pygame.Rect(j * square_size, i * square_size, square_size, square_size)
        row.append(square_rect)
    squares.append(row)


object_rect = pygame.Rect(0, 0, square_size, square_size)


running = True
while running:

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False
        elif event.type == pygame.KEYDOWN:

            if event.key == pygame.K_UP:
                if object_rect.top > 0:
                    object_rect.top -= square_size
            elif event.key == pygame.K_DOWN:
                if object_rect.bottom < screen_size[1]:
                    object_rect.top += square_size
            elif event.key == pygame.K_LEFT:
                if object_rect.left > 0:
                    object_rect.left -= square_size
            elif event.key == pygame.K_RIGHT:
                if object_rect.right < screen_size[0]:
                    object_rect.left += square_size


    screen.fill((255, 255, 255))


    for row in squares:
        for square_rect in row:
            pygame.draw.rect(screen, (0, 0, 0), square_rect, 1)


    pygame.draw.rect(screen, (255, 0, 0), object_rect)

    pygame.display.flip()