import pygame


def initialize():
    """
    This function sets some global constants (i.e., the values of these global
    variables never change).
    """
    pygame.init()

    # set up the display window
    global width, height, screen
    width = 640
    height = 480
    screen = pygame.display.set_mode((width,height))

    # load the pictures
    global guy
    guy = pygame.image.load("WalkingSquare1.gif")
    guy = guy.convert()



def run_game():

    # initialize the guy's position and speed
    g_x = 100
    g_y = 100
    g_speed_x = 0
    g_speed_y = 0

    # start clock
    clock = pygame.time.Clock()
    
    keepGoing = True

    while (keepGoing):

        dt = clock.tick()

        # go through all events that happened and check ...
        for event in pygame.event.get():
            
            # ... whether the event was a quit event
            if event.type == pygame.QUIT:
                keepGoing = False


        # set background color
        screen.fill(pygame.color.Color("green"))

        # draw image
        screen.blit(guy,(g_x,g_y))

        # update display
        pygame.display.update()


def done():
    
    pygame.quit()
    


def main():

    initialize()

    run_game()

    done()



main()