科赫曲线参数怎么改Python怎么改

图里参数怎么改，请程序员们帮忙看看Python请问请问真的不会，这个参数究竟要怎么改

import turtle
def koch(size, level, proportion=1/3):
    if level!=0:
        for angle in [0, 60, -120, 60]:
            turtle.left(angle)
            koch(size * proportion, level-1)
    else:
        turtle.fd(size)

def main():
    turtle.setup(600, 600)
    turtle.penup()
    turtle.goto(-200, 100)
    turtle.pendown()
    turtle.pensize(2)
    turtle.speed(0)
    turtle.hideturtle()
    turtle.tracer(False) #关闭画笔踪迹开关
    turtle.pencolor('blue')
    level = 5
    koch(400, level)
    turtle.right(120)
    koch(400, level)
    turtle.right(120)
    koch(400, level)
    turtle.done()

if __name__ == '__main__':

    main()