python 畫任意多邊形

urtle是Python內置的圖形庫，在這里，我們需要知道正多邊形內角計算公式：內角=（邊數-2）*180/邊數

可選項：提示輸入一種顏色，進行填充。本程序運行環境是Python3的IDLE。

import turtle

##python中的圖形庫

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

turtle.setup(width=800, height=800, startx=400, starty=0)
turtle.pencolor("white")
#默認中心點開始，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()