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# turtlelab.py: Programming lab for turtle fractal trees.                     #
# CTY Lancaster 2012 Session I, DATA                                          #
# Author: Jon Brandvein                                                       #
# Modified: 06/28/12                                                          #
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# YOUR NAME: 
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from turtle import *
from random import random, randint

# The function random() returns a random value from the range [0, 1).
# The function randint(lo, hi) returns a random integer from the range
# [lo, hi].

t = Turtle()

# Uncomment to have colors take the range [0, 255) instead of [0, 1)
#colormode(255)

# Change the speed. Higher is faster. 0 is as fast as possible.
t.speed(5)
# Skip steps to draw even faster. 1 is normal.
#tracer(10)


# drawpolygon() and drawtriangle() functions, from class.

def drawpolygon(n, side_length):
    extangle = float(360)/n
    for i in range(n):
        t.forward(side_length)
        t.left(extangle)

def drawtriangle(side_length):
    drawpolygon(3, side_length)


# This draws the simplified fern we had in class.

def drawfern(size):
    # Return if we're too small to be noticeable.
    if size < 5:
        return
    
    # The sub-fern sizes are divided by this factor.
    # It should be greater than 1. (Why?)
    factor = 2
    
    # One quarter of the stem size, rounded down
    quarter_size = size/4
    # The exact amount remaining after going two quarter sizes,
    # accounting for rounding error.
    remaining_size = size - (2 * quarter_size)
    
    # Draw the stem.
    t.forward(size)
    
    # Back up to draw the right leaf.
    t.backward(quarter_size)
    t.right(90)
    
    # Draw the right leaf.
    drawfern(size / factor)
    
    # Head back to draw the left leaf.
    t.right(90)
    t.forward(quarter_size)
    t.right(90)
    
    # Draw the left leaf.
    drawfern(size / factor)
    
    # Go back to where we started and correct our orientation.
    t.left(90)
    t.forward(remaining_size)
    t.right(180)


def drawtree(size):
    if size <= 20:
        return
    
    t.color('red')
    t.forward(size)
    
    t.left(30)
    drawtree(size / 3 * 2)
    
    t.right(60)
    drawtree(size / 3 * 2)
    
    t.left(30)
    t.color('blue')
    t.backward(size)


# Code that is not in a function is executed when the program starts,
# like main().

# Setup initial position.
t.left(90)
t.penup()
t.backward(200)
t.pendown()

drawtree(150)
#drawfern(300)

mainloop()