squares.py

import sys
import random
import pygame as pg


class Square(object):
    colors = ["red", "orange", "yellow", "green", "blue", "purple"]
    def __init__(self, center_point):
        self.color = random.choice(self.colors)
        size = random.randint(5, 50)
        self.rect = pg.Rect(0, 0, size, size)
        self.rect.center = center_point
        self.speed = random.randint(1, 10)
        self.x_velocity = random.randint(-1, 1)
        self.y_velocity = random.randint(-1, 1)

    def move(self):
        self.rect.move_ip((self.x_velocity * self.speed,
                                    self.y_velocity * self.speed))

    def update(self, screen_rect, ticks):
        if self.rect.left < 0 or self.rect.right > screen_rect.right:
            self.x_velocity *= -1
        if self.rect.top < 0 or self.rect.bottom > screen_rect.bottom:
            self.y_velocity *= -1
        self.move()

    def draw(self, surface):
        pg.draw.rect(surface, pg.Color(self.color), self.rect)


def main():
    pg.init()
    screen = pg.display.set_mode((640, 480))
    clock = pg.time.Clock()
    fps = 30
    squares = []

    while True:
        for event in pg.event.get():
            if event.type == pg.QUIT:
                pg.quit()
                sys.exit()
            elif event.type == pg.MOUSEBUTTONDOWN:
                new_square = Square(event.pos)
                squares.append(new_square)

        screen.fill(pg.Color("black"))
        for square in squares:
            square.update(screen.get_rect(), ticks)
        for square in squares:
            square.draw(screen)
        pg.display.update()
        clock.tick(fps)


if __name__ == "__main__":
    main()