import pygame

pygame.init()

screen = pygame.display.set_mode((640, 480))
pygame.display.set_caption("Simple Scene")

SKY    = (135, 206, 235)
GROUND = ( 80, 140,  60)
SUN    = (255, 230,  50)
TRUNK  = (100,  60,  20)
LEAVES = ( 40, 140,  40)

running = True
while running:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            running = False

    screen.fill((0, 0, 0))

    # sky
    pygame.draw.rect(screen, SKY,    (0,   0, 640, 240))
    # ground
    pygame.draw.rect(screen, GROUND, (0, 240, 640, 240))
    # sun
    pygame.draw.circle(screen, SUN, (560, 60), 50)
    # tree trunk
    pygame.draw.rect(screen, TRUNK,  (300, 320, 40, 100))
    # tree top
    pygame.draw.circle(screen, LEAVES, (320, 300), 60)

    pygame.display.flip()

pygame.quit()