import turtle

turtle.speed(400) # you can set speed to 1 for testing

turtle.left(90) # turns turtle so facing up

# code to draw the first iteration of the tree

#turtle.forward(100)
#turtle.left(30)
#turtle.forward(100)
#turtle.backward(100)
#turtle.right(60)
#turtle.forward(100)
#turtle.backward(100)
#turtle.left(30)
#turtle.backward(100)


def tree(size, iter):
    """Draws tree of given size and iter number
    of iterations."""
    if iter == 0:
        turtle.forward(size)
        turtle.backward(size)

    else:
        # the nth iteration is given by replacing each branch of a simple tree
        # with a scaled copy of the (n-1)th iteration
        turtle.forward(size/2.0)
        turtle.left(30)
        tree(size/2.0,iter-1)
        turtle.right(60)
        tree(size/2.0,iter-1)
        turtle.left(30)
        turtle.backward(size/2.0)

tree(200.0,4)

turtle.mainloop()