python绘图四叶草

import turtledef draw_shapes():    window = turtle.Screen()    window.bgcolor("red")    flower = turtle.Turtle()    flower.speed(10)    flower.shape("arrow")    flower.right(45)    for i in range(1,37):        for j in range(1,5):            draw_circle(flower,i,"green")            flower.left(90)    flower.right(45)    flower.color("green")    flower.forward(500)    window.exitonclick()def draw_circle(circle,radius,color):    circle.color(color)    circle.circle(radius)draw_shapes()