Koch Snowflake Small Package

源程序如下：
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(600,600)
turtle.penup()
turtle.goto(-200, 100)
turtle.pendown()
turtle.pensize(2)
level = 3 # 阶数
koch(400,level)
turtle.right(120)
koch(400,level)
turtle.right(120)
koch(400,level)
turtle.hideturtle()
main()
运行结果如下图：