分形树的绘制

import turtle
def draw_tree(length):
    if length > 5:
        turtle.forward(length)
        print("前进了",length)
        turtle.right(20)
        print("向右转了20度")
        draw_tree(length-15)
        turtle.left(40)
        print("向左转了40度")
        draw_tree(length-15)
        turtle.right(20)
        print("向右转了20度")
        turtle.backward(length)
        print("向后退了",length)
def main():
    turtle.left(90)
    turtle.penup()
    turtle.backward(80)
    turtle.pendown()
    draw_tree(100)
    turtle.exitonclick()
if __name__==‘__main__‘:
    main()