import sys
import pygame

pygame.init()
screen = pygame.display.set_mode((960, 720))
done = False
block_size = 60
WHITE = (255, 255, 255)
BLUE = (0, 0, 255)
screen.fill(WHITE)


def main():
    for y in range(400):
        for x in range(300):
            rect = pygame.Rect(x * block_size, y * block_size, block_size - 1, block_size - 1)
            pygame.draw.rect(screen, BLUE, rect)

    while not done:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                pygame.quit()
                sys.exit()
        pygame.display.update()


main()