Haskell Fundamentals - Pattern Matching

This topic is for the [Pattern Matching][] exercise in the [Haskell Fundamentals][] trail. Post any questions, corrections, or pointers you have to share with other Upcase subscribers.
[Pattern Matching]: https://exercises.upcase.com/exercises/pattern-matching
[Haskell Fundamentals]: https://thoughtbot.com/upcase/haskell-fundamentals