There are plenty of design patterns floating around the programming world,
and in time, a particular set of 23 of them has become accepted as the stan-
dard set. These patterns were first corralled in a book named Design Patterns:
Elements of Reusable Object-Oriented Software (1995, Pearson Education, Inc.
Publishing as Pearson Addison Wesley) by Erich Gamma, Richard Helm,
Ralph Johnson, and John Vlissides — who have since been called the Gang of
Four, or GoF, for short. And those 23 design patterns became known as the
GoF design patterns....