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]: Learn Haskell Fundamentals | Haskell Online Tutorial by thoughtbot