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.