After some further toil, his efforts were rewarded, and a very shabby door-mat lay exposed to view.

These constructs support the object-oriented form of encapsulation, where only the essential public abstraction of a class or trait is exposed and implementation information is hidden from view.

Assign code to regions that are hidden or exposed, depending on the detail of the view (for example, you can hide error-checking code when you want to analyze just the algorithm).