design for change

creating an object by specifying a class explicitly -- Abstract Factory, Factory Method, Prototype
dependence on specific operations -- Chain of Responsibilty, Command
dependence on hardware & software platforms -- Abstract Factory, Bridge
dependence on object implementation or representation --Abstract Factory, Bridge, Memento, Proxy
algorithm dependence -- Builder, Iterator, Strategy, Template Method, Visitor
extending functionality by subclassing -- Bridge, Chain, Composite, Decorator, Observer
tight coupling -- Abstract Factpry, Bridge, Chain of Responsibilities, Command, Facade, Mediator, Observer
inability to alter classes conveniently -- Adaptor, Decorator, Visitor