Objects are encapsulated. Requests can identify objects. New objects can be created. Operations can be generic. Objects can be classified in terms of their services.
Objects can have common implementations.
Implicitly an object can act as a client merely by requesting services from other objects as part of the process whereby it services its own clients. The relation between a client object and its server is that of collaborations . New objects can be created. An object that can only be accessed by clients by issuing requests . Beware of confusing encapsulation with information hiding .