Sierpinski triangle fractal using turtle graphics

import turtle

def sierpinski(length, depth):

    if depth == 0:

        for i in range(3):

            turtle.forward(length)

            turtle.left(120)

    else:

        sierpinski(length / 2, depth - 1)

        turtle.forward(length / 2)

        sierpinski(length / 2, depth - 1)

        turtle.backward(length / 2)

        turtle.left(60)

        turtle.forward(length / 2)

        turtle.right(60)

        sierpinski(length / 2, depth - 1)

        turtle.left(60)

        turtle.backward(length / 2)

        turtle.right(60)

turtle.speed(0)

turtle.hideturtle()

turtle.penup()

turtle.goto(-200, -200)

turtle.pendown()

sierpinski(400, 5)

turtle.exitonclick()