More design patterns

Factory method:
"The Factory method pattern defines an interface for creating an object, but lets subclasses decide which class to instantiate. Factory method lets a class defer instantiation to subclasses."

Abstract factory:
"The abstract factory pattern provides an interface for creating families of related or dependent objects without specifying their concrete classes"

Singleton:
"The singleton pattern ensures that a class has only one instance, and provides a global point of access to it."

Command:
"The Command pattern encapsulates a request as an object, thereby letting you parameterise other objects with different requests, queue or log requests, and support undoable operations."

Adapter:
"The adapter pattern converts the interface of a class into another interface the clients expect. Adapter lets classes work together that couldn't otherwise because of incompatible interfaces."

Facade:
"The Facade pattern provides a unified interface to a set of interfaces in a subsystem. Facade defines a higher-level interface that makes the subsystem easier to use."

Template method:
"The Template method pattern defines the skeleton of an algorithm in a method, deferring some steps to subclasses. Template method lets subclasses redefine certain steps of an algorithm without changing the algorithm's structure."

Iterator:
"The Iterator pattern provides a way to access the elements of an aggregate object sequentially without exposing its underlying representation."

Composite:
"The Composite pattern allows you to compose objects into tree structures to present part-whole hierarchies. Composite lets clients treat individual objects and compositions of objects uniformly."

State:
"The State pattern allows an object to alter its behavior when its internal state changes. The object will appear to change its class."

Proxy:
"The Proxy pattern provides a surrogate or placeholder for another object to control access to it."