I'd prefer to see these values used in line in the specs below rather than making `let` declarations for them.  The `let` declarations force you to scroll back and forth to understand the full expression, and there's nothing special about these values that makes them automatically useful for all examples below.  The duplication in any examples that happen to re-use these same values is purely incidental and isn't a DRY violation as these don't represent a piece of knowledge.