# Importing the Pygame library for building games and multimedia applications.
import pygame
# Importing the sys module to exit the program.
import sys
# Importing constants from pygame.locals module.
from pygame.locals import *

# Initializing all Pygame modules.
pygame.init()

# Creating a window surface with a size of 300x300 pixels.
displaysurface = pygame.display.set_mode((300,300))

# Creating a surface with a size of 50x50 pixels and filling it with green color.
mySurface = pygame.Surface((50,50))
mySurface.fill((0,255,0))

# Creating another surface with a size of 100x50 pixels and filling it with green color.
mySurface2 = pygame.Surface((100,50))
mySurface2.fill((0,255,0))

# Main game loop that runs indefinitely until the program is exited.
while True:
    # Iterating through each event that has occurred.
    for event in pygame.event.get():
        # If the event is the user closing the window...
        if event.type == QUIT:
            # ...quit Pygame and exit the program.
            pygame.quit()
            sys.exit()
    
    # Drawing the first surface at position (50,50) on the display surface.
    displaysurface.blit(mySurface, (50,50))
    # Drawing the second surface at position (50,150) on the display surface.
    displaysurface.blit(mySurface2, (50,150))

    # Updating the display to show any changes.
    pygame.display.update()