#!/usr/bin/env python3
"""
This template describes a tree that is drawn recursively using 
the turtle module.
"""

__author__ = ""
__version__ = ""

from turtle import *

def branch(t, length):
    """We'll need to have as parameters:
    * the turtle we're using to draw the tree
    * the length of this branch that we're about to draw
    Additional parameters that can be added in subsequent
    versions of the progrm include line thickness, color, 
    angle...
    """
    
    # if the length has gotten too small (base case):

        return

    # otherwise:

        # draw a line forward of the given length

        # turn the turtle to the right some number of degrees

        # call the branch function recursively with a smaller branch length
        # (At some point, upon returning from THIS branch, we'll be back 
        # (at the end point of THIS branch, at which time...)

        # turn the turtle to the left twice the degrees as before

        # call the branch function recursively as before

        # turn the turtle back to the right (so that it is in it's original
        # "forward" position

        # move the turtle back of the given length

        return

def main():
    win = Screen()
    t = Turtle()
    t.penup()   # don't leave a line while we're moving the turtle
    t.goto(0,-200)  # move to this location on the screen:
                    # horizontally centered, and 200 pixels below the center
    t.left(90)      # aim turtle "up" to create our first branch
    t.pendown()     # pendown--we're ready to draw lines!
    t.speed(0)      # let's draw them as fast as possible
    branch(t, 100)  # It's a branch, but really it's our "trunk"
    win.exitonclick()   # Leave the window open so we can admire our work

if __name__ == "__main__":
    main()