Points of a circle python code

# POINTS OF A CIRCLE

# By Jaseman - 21st August 2012

import os, pygame; from pygame.locals import *
from math import sin, cos, pi
pygame.init(); clock = pygame.time.Clock()
os.environ['SDL_VIDEO_WINDOW_POS'] = 'center'
pygame.display.set_caption("Points Of A Circle")
screen=pygame.display.set_mode((600,600),0,32)

background=pygame.Surface((600,600))
background.fill((0,0,192))

dot=pygame.Surface((8,8))
pygame.draw.circle(dot,(255,255,255),(4,4),4,0)
dot.set_colorkey([0,0,0])

screen.blit(background,(0,0))
screen.blit(dot,(300-4,300-4)) # Paste a dot in the centre of the screen
# 300=half screen width 4=half dot width

radius = 200
points = 90

angleStep = pi *2 / points
for a in range(0,points):
	x = sin(a * angleStep)*radius
	y = cos(a * angleStep)*radius
	screen.blit(dot,(x+300-4,y+300-4)) # Paste dots in a circle


pygame.display.update()
pygame.time.wait(30000)