Getting to know you

• Python is a highly popular programming language, used by many large organisations.
• Facebook, NASA, IBM, Google and Yahoo among others all use it extensively.
• It is considered by many to be one of the easiest languages to pick up.

• One of the big attractions of Python is that many 'libraries' are available to provide it with extra functionality.
• A library is a set of extra functions that help perform different types of task. There are libraries for advanced maths, graph drawing, graphics, game writing, random numbers and so forth.
• We're going to use a fun library called 'Turtle', which allows for the convenient drawing of lines and shapes.

• Load up the Python Development, called IDLE.
• You'll be presented with the Python Shell window, which looks like this…

• With the mouse in the shell window, type the following at the >>> Prompt.
• Hit enter after each line.
• (Note: Make sure you write Screen with a capital letter!

import turtle
wn=turtle.Screen()
wn.bgcolor("lightgreen")
wn.title("Turtle Power")

• A graphics window (currently empty) will appear that we can draw into.
• We've called our screen object, "wn". Every time we want Python to control somthing to do with this window, we'll need to put wn. in front of the command.
• We also changed the background colour, and put a title on the window.
• Let's add a "turtle" to the screen. We can move this arounnd the screen to draw shapes and patterns. We'll call our turtle, "Tess".

tess=turtle.Turtle()
tess.color("hotpink")
tess.pensize(5)
tess.shape("turtle")

• When we created a tess object, we then went on to set some of her properties - colour, thickness of the lines she'll draw and how she appears on the screen.
• Incidentally, a full colour list can be found here.
• We could add other turtle objects too, if we wanted, and have several drawing shapes on the screen. We might have a look at that later on.
• Next, lets start to draw. Type…

tess.forward(100)
tess.left(90)
tess.forward(100)
tess.left(90)
tess.forward(100)
tess.left(90)
tess.forward(100)
tess.left(90)

• Your turtle should have traced a square shape for you.