python 画任意多边形

urtle是Python内置的图形库，在这里，我们需要知道正多边形内角计算公式：内角=（边数-2）*180/边数

可选项：提示输入一种颜色，进行填充。本程序运行环境是Python3的IDLE。

import turtle

##python中的图形库

colors=["red","yellow","purple","blue","black","green"]
turtle.pensize(2)

turtle.setup(width=800, height=800, startx=400, starty=0)
turtle.pencolor("white")
#默认中心点开始，gisoracle
turtle.goto(0,300)

for num in range(3,20):
    turtle.pencolor(colors[num%6])

    angle = 180 - (num - 2) * 180 / num

    for i in range(num):
        turtle.begin_fill()
        turtle.forward(100)
        turtle.right(angle)
        turtle.end_fill()
turtle.done()