#!/usr/bin/env python

#original code from Game Development with Python and Pygame by Will McGugan

import pygame
from pygame.locals import *
from sys import exit
from math import *

pygame.init()
screen = pygame.display.set_mode((640, 480), 0, 32)

j=0

while True:
        
    for event in pygame.event.get():
        if event.type == QUIT:
            exit()            
    
    screen.fill((0, 0, 0))
    
    mouse_pos = pygame.mouse.get_pos()
    random_pos = (j%640, 240 + 40*sin(j/15))
    
    for x in xrange(0,640,20):
        pygame.draw.line(screen, (255, 0, 0), (x, 0), random_pos,3)
        pygame.draw.line(screen, (255, 0, 0), (x, 479), random_pos,3)
        
    for y in xrange(0,480,20):
        pygame.draw.line(screen, (0, 255, 0), (0, y), random_pos,3)
        pygame.draw.line(screen, (0, 255, 0), (639, y), random_pos,3)

    j = j+5

    pygame.display.update()