This is going to be our first experience with something that's a little more like a concept...
But, it's really not that bad. We'll just do a little at a time!
You can think of a function as being a box with a special rule... stuff goes in the box... and stuff comes out of the box.
Let's start with a movie title box:
THE RULE: Spit out the first letter of the movie title.
(Only movie titles can go in.)