科勒曲线

import turtle
def koch(size, n):
    if n == 0:
        turtle.fd(size)
    else:
        for angle in [0, 60, -120, 60]:
           turtle.left(angle)
           koch(size/3, n-1)
def main():
    turtle.setup(1500,900)
    turtle.speed(0)  #控制绘制速度
    
    turtle.penup()
    turtle.goto(-700,150)
    turtle.pencolor("red")
    turtle.pendown()
    turtle.pensize(2)
    koch(400,1)     # 阶数1

    turtle.penup()
    turtle.goto(-200, 150)
    turtle.pendown()
    turtle.pensize(2)
    koch(400,2)     # 阶数2

    turtle.penup()
    turtle.goto(300, 150)
    turtle.pendown()
    turtle.pensize(2)
    koch(400,3)     # 阶数3

    turtle.penup()
    turtle.goto(-700, -150)
    turtle.pencolor("violet")
    turtle.pendown()
    turtle.pensize(2)
    koch(400,4)     # 阶数4

    turtle.penup()
    turtle.goto(-200, -150)
    turtle.pendown()
    turtle.pensize(2)
    koch(400,5)     # 阶数5

    turtle.penup()
    turtle.goto(300, -150)
    turtle.pendown()
    turtle.pensize(2)
    koch(400,6)     # 阶数6
    
    turtle.hideturtle()
main()