One of the great things in computer programming
is once you've taught a computer how to do

an action, you can call that function again.
You give it a name and then you can call it.

That's really like extending the language.
In the program we built, we learned how to

draw a square by moving and turning four times.
We can take that function and give it a name,

draw a square so that any time we want to
do that, we simply say draw a square and it

will go back and invoke that function, that
code and it will get done for us. We've added

that concept to our programming language.
In this puzzle, we have already created a

draw a square function for you. You'll see
it in the toolbox as a green block. What you'll

need to do is write the same code you wrote
before to draw a square and put it in this

function. To do that, click on the edit option
in the green draw a square block. This will

open up the function editor. The function
editor has three parts. A place where you

name your function. This will appear on the
green block before that function. Then write

out a short description of what your function
is supposed to do. In this case, it's supposed

to draw a square. The white space below this
is the work space and works just like the

work space you've already been using. Drag
and drop blocks from the toolbox into this

work space. Remember to put the blocks that
create a square inside the green wrapping

block for the function. Once you're done,
click on save and exit. This will take you

back to the main puzzle work space. Now you
can use the draw the square function block

just like any other block to solve the puzzle.