"""
Demonstrates:
  -- LOOPS (doing something repeatedly) and
  -- using OBJECTS
via Turtle Graphics.

Concepts include:
 * Using OBJECTS:
   -- CONSTRUCT an INSTANCE of a CLASS (we call such instances OBJECTS).
   -- Make an object  ** DO **  something by using a METHOD.
   -- Reference an object's  ** DATA **  by using an INSTANCE VARIABLE.

 * LOOPS:
   -- Using a FOR expression like this:
         for k in range(41):
             blah
             blah
             blah

     The above repeats the body of the FOR expression 41 times.
     The name  k  is:
            0 the first time the body runs,
       then 1 the next time the body runs,
       then 2 the next time the body runs,
         etc
       then 40 the last time the body runs.
     Note how the BODY of the loop (the code that is repeated 41 times)
     is INDENTED.

 * ASSIGNMENT and NAMES
  -- ASSIGNING a VALUE to a NAME (aka VARIABLE), as in these examples:
        jack = 45
        jill = "ran down the hill"
        size = size - 12

 * The DOT trick: If you type expressions like the following,
     pausing after typing the DOT (period, full stop),
     then the window that pops up give lots of clues for what you can do!
        rg.
        rg.SimpleTurtle().
        rg.Pen().
        rg.PaintBucket().

Authors: David Mutchler, Vibha Alangar, Dave Fisher, Matt Boutell, Mark Hays,
         Mohammed Noureddine, Sana Ebrahimi, Sriram Mohan, their colleagues and
         PUT_YOUR_NAME_HERE.
"""
import rosegraphics as rg

###############################################################################
# One window, for two examples.
###############################################################################
window = rg.TurtleWindow()

###############################################################################
# Example 1.
###############################################################################
blue_turtle = rg.SimpleTurtle("turtle")
blue_turtle.pen = rg.Pen("midnight blue", 3)
blue_turtle.speed = 20  # Fast

# The first square will be 300 x 300 pixels:
size = 300

# Do the indented code 6 times.  Each time draws a square.
for k in range(6):

    # Draw a square of the given size:
    blue_turtle.draw_square(size)

    # Move a little below and to the right of where the previous
    # square started.  Do this with the pen up (so nothing is drawn).
    blue_turtle.pen_up()
    blue_turtle.right(45)
    blue_turtle.forward(10)
    blue_turtle.left(45)

    # Put the pen down again (so drawing resumes).
    # Make the size for the NEXT square be 12 pixels smaller.
    blue_turtle.pen_down()
    size = size - 12

###############################################################################
# Example 2.  It shows how to speed up the animation.
###############################################################################
window.tracer(100)  # Bigger numbers make the animation run faster

another_turtle = rg.SimpleTurtle("triangle")
another_turtle.pen = rg.Pen("magenta", 1)
another_turtle.backward(50)

# The name k takes on the values 0, 1, 2, ... 499 as the loop runs
for k in range(500):
    another_turtle.left(91)
    another_turtle.forward(k)

window.close_on_mouse_click()