import pygame


## This recursive function draws a circle with increasingly smaller
## circles nested inside. (I use yet another option of how to make
## sure that the colors are alternating.)

def draw_recursive_circle(win, x, y, radius, color, othercolor):

    pygame.draw.circle(win, color, (x,y), radius)

    if radius > 20:
        draw_recursive_circle(win, x, y, radius-20, othercolor, color)
    


def run_game():
    
    ## Initialize the pygame submodules and set up the display window.

    pygame.init()

    width = 640
    height = 480
    my_win = pygame.display.set_mode((width,height))


    ## The game loop starts here.
    
    keepGoing = True    
    while (keepGoing):

        ## Handle events.

        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                keepGoing = False


        ## Draw picture and update display

        my_win.fill(pygame.color.Color("darkblue"))

        draw_recursive_circle(my_win, width/2, height/2, height/2, pygame.color.Color("orange"), pygame.color.Color("magenta"))

        pygame.display.update()

    ## The game loop ends here.

    pygame.quit()


## Call the function run_game.

run_game()