图案一，半圆

import turtle

turtle.circle(50, 180)

turtle.left(90)

turtle.forward(100)

图案二，同心圆

import turtle

turtle.circle(100)

turtle.right(90)

turtle.penup()

turtle.forward(50)

turtle.pendown()

turtle.left(90)

turtle.circle(150)

图案三，红心

import turtle

turtle.color('red')

turtle.begin_fill()

for i in range(5):

    turtle.forward(100)

    turtle.right(144)

turtle.end_fill()

turtle.hideturtle()

图案四，四叶草

import turtle

turtle.fillcolor("green")

turtle.begin_fill()

for i in range(4):

    turtle.right(90)

    turtle.circle(100,180)

turtle.end_fill()

图案五，螺旋正方形

import turtle

turtle.width(3)

d=0

k=5

for j in range(10):

    for i in range(4):

        turtle.forward(k)

        d+=(90+1)

        turtle.seth(d)

        k+=5