# -*- coding: utf-8-sig -*-

# NOTE FOR CANOPY USERS: 'turtle' is based on a GUI called 'tkinter' which is different from 
# what Canopy is based on that's called 'pylab'. Hence, in order to be able to use turtle in
# Canopy, you should do the following:
# Click on Canopy - Preferences - Python, then uncheck 'Use Pylab'.

# Source: http://www.daniweb.com/software-development/python/code/216557/turtle-graphics-python
# Official python-turtle documentation: http://docs.python.org/2/library/turtle.html

from turtle import *
import time

speed("slowest")  #option 'fastest' will be handy for long iterations

tracer(1)  # only the nth screen update is shown. Set to 0 to turn tracer off.

# The pen/turtle starts at the center (x=0, y=0) of the turtle display area by default.

pencolor("green")

# While the pen is up, turtle can't draw; this is useful if you want the turtle to 
# go to a different location.

penup()

# Have the turtle go to the center of the screen
goto(0,0)

# put the pen down so the turtle can draw
pendown()

# Draw a circle with radius = 50 units. 
# The turtle doesn't draw the circle with its center at (0,0) however; it only draws
# a circle that passes through the point (0,0).
circle(50)

time.sleep(2)  # wait for 2 seconds

# draw blue 100x100 squares
pencolor(0.9,0.3,0.7)  #(red,green,blue) triplet

# At this point, by default, the turtle is facing east (right)
for deg in range(0, 61, 20):
    
    right(90 + deg)  # turn right by angle = 90 + deg
    
    forward(100)  # step forward by 100 units while drawing a line
    
    right(90)
    
    forward(100)
    
    right(90)
    
    forward(100)
    
    right(90)
    
    forward(100)
    
    time.sleep(1)
    
    ps = pensize()  # get curent size of pen
    
    pensize(ps + 1)  # set new size of pen
    
penup()

goto(-150,-120)

color("red")

write("Done!")

#IMPORTANT: if you don't do the following, the window might freeze
done()  

#finally close the window to release the console