Raspberry Pi For Kids For Dummies

Chapter 12

Throw Shapes with Turtles

Python includes a turtle. It’s not a real turtle, because you’d have to feed it and look after it — which would be cute, but probably wouldn’t teach you much about computers.

Meet the Python Turtle

The Python turtle is a drawing bot. You can steer it around the screen and make it draw shapes. With only a little programming magic, you can make awesome pictures that will make your friends believe you’re a computer genius.

On the Raspberry Pi, the turtle is built right into Python. To use it, add a single line to the start of your code, like this:

import turtle

That’s all you need. You can now write commands for the turtle. When you run your code, the turtle appears in a special window. It draws a line as it moves. It’s that simple!

Figure 12-1 shows the turtle drawing a complicated shape using a few simple commands.

Figure 12-1

Get started with turtle commands

Turtle programming is really, really easy because there are only three kinds of commands:

• The first kind turns the turtle.
• The second kind moves it and draws a line.
• The third kind turns drawing on and off, changes the pen color, and does other useful stuff, like clear the screen.

Most turtle programs have a block of starting code to set up the turtle and maybe define useful numbers ...