import turtle

def double_trouble(yertle, length):
    if length > 20:
        yertle.forward(length)
        branch = length * (2.0 / 3)

        turtle_left = yertle.clone()
        turtle_left.color('blue')
        turtle_left.left(30)
        double_trouble(turtle_left, branch)

        turtle_right = yertle.clone()
        turtle_right.color('red')   
        turtle_right.right(30)
        double_trouble(turtle_right, branch)
        
        yertle.backward(length)
    yertle.hideturtle()





t = turtle.Turtle()
t.penup()
t.goto(0, -150)
t.pendown()
t.left(90)
#double_trouble(t, 120)