Slider function article

This is just the beginning of the "A Slider Function" article!  I just wanted to share where I am starting from.  I am following a similar format to how you handled "A Button Function" to allow for a familiarity to develop in the processes you highlight:

-Breaking down a complex problem into simpler component parts.
-Reinforcing how variables makes code more readable and easier to maintain.
-Emphasizing code reusability with functions.
maybe passed into the <code>rect()</code> function?