Python科赫曲线

import turtle as t
def koch(size,n):
    if n==0:
        t.fd(size)
    else:
        for angle in [0,60,-120,60]:
            t.left(angle)
            koch(size/3,n-1)
if __name__=='__main__':
    t.setup(1000,1000)
    t.pen(speed=0,pendown=False,pencolor='blue')
    a,n=400,4
    t.goto(-a/2,a/2/pow(3,0,5))
    t.pd()
    for i in range(3):
        koch(a,n)
        t.right(120)
    t.ht()
    t.done()