mouse.py

import pygame
import random

BLACK = (0,0,0)
RED = (255, 0, 0) #These tuples are RGB by the way
WHITE = (255, 255, 255)

pygame.init()
WIDTH = 450
HEIGHT = 600
screen = pygame.display.set_mode([WIDTH, HEIGHT])

another_loop = True
clock = pygame.time.Clock()

font = pygame.font.Font(None, 36) #Make a font
textx = 100
texty = 400

circle_x = 50
circle_y = 50
  
while another_loop:
    # --- Basic Event Processing
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            another_loop = False

    # Every loop we will wipe the screen and redraw images
    screen.fill(BLACK)

    text = font.render("Hi there", 1, WHITE) #Use font to generate text image
    if pygame.mouse.get_pressed()[0]:
        text = font.render("Hi there", 1, RED) #Use font to generate text image
    
    #Draw the new screen here:
    screen.blit(text, (100, 100)) #stick that image on screen

    screen.blit(text, (textx, texty)) #possibly in multiple places

    textx, texty = pygame.mouse.get_pos()

    pygame.draw.circle(screen, RED, (circle_x, circle_y), 30)
    circle_y = (circle_y + 5) % HEIGHT

    #This sets the frames per second
    clock.tick(60)
 
    #This puts the new stuff you've drawn on screen
    pygame.display.flip()

#When we've left the while loop exit pygame 
pygame.quit()