pygame_draw_rectangle.py

import pygame
import sys #will use the exit function

#Loads all the main pygame modules and initializes them
pygame.init()

screen_width=640
screen_height=480

red = (255,0,0)

#Create a new Surface with the dimensions listed above
screen=pygame.display.set_mode((screen_width, screen_height))

#Loop forever:
while True:
    
    #The following makes the window close when clicking the "X" or exit button
    #Without this, the window will not close, and will need to be killed
    #with the task manager
    for event in pygame.event.get():
        if event.type == pygame.QUIT: sys.exit()
        
    #Rect takes (left, top, width, height)
    myRectangle = pygame.Rect(50,100,200,300)
    
    #(Which surface to draw on, what color, a rectangle)
    pygame.draw.rect(screen, red, myRectangle)
    
    #Apply all the changes we've made to the screen surface
    #And draw them to the screen
    pygame.display.flip()