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A software design pattern concerned with allocating behavior and communication responsibilities among objects. Observer patterns notify dependents, while a command pattern represents a request as an object.

A software design pattern organizing how software objects are created. A prototype pattern creates an object by asking an existing example to copy itself, letting a client choose a concrete configuration at runtime through an object interface.

True. A small proof-of-concept implementation makes the participants, delegation, and extension points of a software design pattern concrete. Trying a second strategy, an extra decorator, or another observer tests what changes locally and what assumptions remain. This supports learning when the arrangement is useful; it does not establish that every production system needs it.

False as a general claim. An appropriately chosen software design pattern can make expected variation easier: a new strategy or decorator can be supplied through an existing object interface. An unnecessary pattern can add indirection and make some changes harder, so applying one is not an automatic guarantee of flexibility either.

True. A named software design pattern supplies shared vocabulary for recurring arrangements of responsibilities and interactions. Saying “observer” can identify subject registration and callbacks without first reproducing every implementation detail, provided developers still agree on the actual contract.

True. Refactoring an existing implementation toward a software design pattern can be preferable once repeated structure and actual variation are visible. Existing behavior supplies a concrete contract to preserve, and tests can check that preservation. Starting from a pattern is appropriate when its problem is already established, but the pattern's name alone is not evidence that its extra structure is needed.

A software design pattern organizing composition of classes and objects into larger structures. The decorator pattern wraps a component behind the same object interface, delegating existing work and adding one responsibility. Wrappers can be nested without declaring a new class for each combination.