Circle

import pygame
pygame.init()
FPS = 15
SCREEN_SIZE = WIN_WIDTH, WIN_HEIGHT = 400, 400
gray = (170,170,170)
yellow = (230, 200, 20)
White = (255,255,255)
rect_width = WIN_WIDTH // 2
rect_height = WIN_HEIGHT // 2
rect_size = (rect_width, rect_height)
BACK_COLOR = White
CIRCLE_COLOR = yellow

clock = pygame.time.Clock()
sc = pygame.display.set_mode(SCREEN_SIZE)
sc.fill(BACK_COLOR)

rect_1 = pygame.Rect((0, 0), rect_size)
rect_2 = pygame.Rect((rect_width, 0), rect_size)
rect_3 = pygame.Rect((rect_width, rect_height), rect_size)
rect_4 = pygame.Rect((0, rect_height), rect_size)

surf_1 = pygame.Surface(rect_size)
surf_2 = pygame.Surface(rect_size)
surf_3 = pygame.Surface(rect_size)
surf_4 = pygame.Surface(rect_size)

surf_1.fill(BACK_COLOR)
surf_2.fill(BACK_COLOR)
surf_3.fill(BACK_COLOR)
surf_4.fill(BACK_COLOR)

sc.blit(surf_1, rect_1)
sc.blit(surf_2, rect_2)
sc.blit(surf_3, rect_3)
sc.blit(surf_4, rect_4)

circle_update = (rect_1, rect_2, rect_3, rect_4)

while 1:
    for i in pygame.event.get():
        if i.type == pygame.QUIT:
            pygame.quit()
            exit()
        if i.type == pygame.KEYDOWN:
            if i.key == pygame.K_ESCAPE:
                pygame.quit()
                exit()
            if i.key == pygame.K_1:
                circle_update = (rect_1, rect_3)
            elif i.key == pygame.K_2:
                circle_update = (rect_2, rect_4)
            elif i.key == pygame.K_0:
                circle_update = (rect_1, rect_2, rect_3, rect_4)


    if CIRCLE_COLOR == yellow:
        CIRCLE_COLOR = gray
    elif CIRCLE_COLOR == gray:
        CIRCLE_COLOR = yellow
    pygame.draw.circle(sc, CIRCLE_COLOR, (WIN_WIDTH // 2, WIN_HEIGHT // 2), 100)
    pygame.display.update(circle_update)
    pygame.time.delay(500)

    clock.tick(FPS)