Pygame script to create a waving flag effect

waves.py

import pygame

def main():
	arc = 0.25
	base_angle = 0.0
	circle_width = 20
	circle_height = 20
	fps = 60
	speed = 0.1
	window_width = 800
	window_height = 600
	x_scale = 0.4
	y_scale = 0.3

	pygame.init()
	screen = pygame.display.set_mode((window_width, window_height))
	background = pygame.Surface(screen.get_size())
	background = background.convert()
	clock = pygame.time.Clock()
	
	while 1:
		clock.tick(fps);
		for event in pygame.event.get():
			if event.type == pygame.QUIT: 
				sys.exit()

		base_angle += speed
		
		background.fill((0,0,0))
		
		for y in range(1, (window_height / circle_height)-1):
			for x in range(1, (window_width / circle_width)-1):
				angle = base_angle + (x*x_scale) + (y*y_scale)
				pygame.draw.arc(background, (200,200,200),(x*circle_width, y*circle_height, circle_width, circle_height), angle, angle+arc)

		screen.blit(background, (0,0))
		pygame.display.flip()

if __name__ == "__main__":
	main()