Aggregate pattern: a version of the Composite pattern with methods for aggregation of children Bridge pattern: decouple an abstraction from its implementation so that the two can vary independently Tombstone: An intermediate "lookup" object contains the real location of an object.[4] Composite pattern: a tree structure of objects where every object has the same interface Decorator pattern: add additional functionality to an object at runtime where subclassing would result in an exponential rise of new classes Extensibility pattern: a.k.a.