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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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just like any other block to solve the puzzle.