绕中心点旋转之五角星

"""
   绕中心点旋转之五角星
   本程序首先算出10个点的坐标，然后把这个形状注册到屏幕的形状字典
"""
import math
from turtle import *

R = 30
r = R * math.sin(math.radians(18))/math.sin(math.radians(36))
points = []

for k in range(5):
    outx =  R * math.cos(math.radians(72*k+36))
    outy =  R * math.sin(math.radians(72*k+36))
    points.append((outx,outy))
    innerx = r * math.cos(math.radians(72*k+36+36))
    innery = r * math.sin(math.radians(72*k+36+36))
    points.append((innerx,innery))

screen = Screen()
star = Shape('polygon',points)
screen.addshape('star',star)

t = Turtle()
t.shape('star')
while 1: t.right(1)