Status: IN
Behavioral object patterns (Strategy, State, Observer, Command, Mediator, Chain of Responsibility) all use object composition rather than inheritance to distribute behavior, directly embodying the GoF's composition-over-inheritance principle as the dominant approach for encapsulating variation.
Behavioral object patterns are composition-over-inheritance put into practice
Depends on (SL): behavioral-patterns-class-vs-object, behavioral-patterns-encapsulate-variation, favor-composition-over-inheritance