It’s November!

It is now the month of November, and the focus of this month’s theme is going to be “Visuals.” We’re going to try and have a diverse set of puzzles that focus on making something interactive and/or visually engaging. This week we are looking at Turtle Graphics and Fractals (though use anything you want to, if you have a different idea of how you’d like to make fractals).

Setup

Python comes with a cool built-in turtle graphics module called turtle. Python Downloads - I’d recommend choosing Python 3

Turtle Graphics

Turtle graphics is an old method of generating graphics. It dates all the way back to the Logo programming language, first released in 1967.

You start with the “Turtle”, a fictional robot that drags a pen across paper (or in our case, the screen). It can be controlled by simple commands.

In Python:

import turtle
t = turtle.Turtle() # make a new turtle

The turtle has a position on the screen and has some orientation angle in degrees.

Here are the basic commands to control the turtle:

The basic commands:

Command	Description
`t.forward(x)`	Move forward `x` pixels
`t.backward(x)`	Move backwards `x` pixels
`t.left(angle)`	Turn in place `angle` degrees to the left
`t.right(angle)`	Turn in place `angle` degrees to the right
`t.penup()`	Lift the pen from the “paper”. This allows moving without drawing a line
`t.pendown()`	Press the pen down onto the “paper”. Now the turtle will resume drawing lines

There are several other commands, but I’ll let you read the docs.

Example Program:

import turtle

# Create our turtle
t = turtle.Turtle()

# Draw a cool pattern by drawing straight lines then making sharp
# angled turns
for i in range(9):
    # Move 300 pixels forward
    t.forward(300)
    # Turn to the right 200 degrees
    t.right(200)

# This keeps the turtle window open at the end of the program
turtle.mainloop()