建立三个菜单，画多边形，画矩形，画椭圆

以下是一个简单的Python代码示例，实现了三个菜单：画多边形、画矩形、画椭圆。你可以在此基础上进行修改和扩展。

import turtle

def draw_polygon():
    sides = int(input("请输入多边形的边数: "))
    length = int(input("请输入多边形的边长: "))
    angle = 360 / sides
    turtle.penup()
    turtle.goto(0, 0)
    turtle.pendown()
    for i in range(sides):
        turtle.forward(length)
        turtle.right(angle)
    turtle.done()

def draw_rectangle():
    width = int(input("请输入矩形的宽度: "))
    height = int(input("请输入矩形的高度: "))
    turtle.penup()
    turtle.goto(-width / 2, -height / 2)
    turtle.pendown()
    turtle.forward(width)
    turtle.right(90)
    turtle.forward(height)
    turtle.right(90)
    turtle.forward(width)
    turtle.right(90)
    turtle.forward(height)
    turtle.done()

def draw_ellipse():
    width = int(input("请输入椭圆的宽度: "))
    height = int(input("请输入椭圆的高度: "))
    turtle.penup()
    turtle.goto(0, -height / 2)
    turtle.pendown()
    turtle.circle(width / 2, 90)
    turtle.circle(height / 2, 90)
    turtle.circle(width / 2, 90)
    turtle.circle(height / 2, 90)
    turtle.done()

while True:
    print("请选择要绘制的图形:")
    print("1. 多边形")
    print("2. 矩形")
    print("3. 椭圆")
    print("0. 退出")
    choice = int(input("请输入选项: "))
    if choice == 1:
        draw_polygon()
    elif choice == 2:
        draw_rectangle()
    elif choice == 3:
        draw_ellipse()
    elif choice == 0:
        break
    else:
        print("无效的选项，请重新输入。")