# -*- coding: utf-8 -*-
import turtle
win = turtle.Screen()
tt = turtle.Turtle()
win.bgcolor('lightgreen')
######
tt.shape('turtle')
def regularPolygon(n, side):
    """
繪製正多邊形(n)，內角為(n-2)*180/n
外角為180-內角
    """
    externalAngle = 180 - (n-2)*180/n
    for i in range(n):
        tt.fd(side)
        tt.lt(externalAngle)

#----------使用上述方法----------#
regularPolygon(3,20)
regularPolygon(4,30)
regularPolygon(5,40)
regularPolygon(6,50)
regularPolygon(7,60)
regularPolygon(8,70)
regularPolygon(9,80)
regularPolygon(10,90)

######
win.exitonclick()