A class factory represented by an interface that exposes multiple related class factories. Each factory creates concrete classes but exposes those classes only through interfaces. The most common example of an abstract factory is an implementation of a graphical user interface or GUI, where each component of the GUI is represented by an abstract interface and is constructed by its own class factory. The whole GUI system could then be instantiated across multiple operating systems just by providing different concrete classes. The GUI system as a whole behaves the same despite the underlying differences in the underlying operating system (and therefore the concrete classes implementing the interfaces).
I did not write any examples of a Abstract Factory design pattern.