On PHPMaster.com today a new tutorial has been posted about using the Facade design pattern to help reduce the complexity of your application. It can help interface between other pieces of code an make using them simpler (a "facade" on top of them).

Design patterns are built to standardize solutions for common problems faced in software development. [...] Facade is a design pattern used in almost every web application, but often without knowing. The term “design pattern” creates a mental image of something complex and difficult to understand. Even though this can be true sometimes, the Facade pattern is simple to implementation. Let’s see what Facade is and what it does to help us write good code.

A simple example is given to help make the concept of a facade clearer - the process behind borrowing a book. As borrowing and returning a book could involve multiple library types, they use a facade to provide a common interface to all of them. With the concrete example in place, they then move on to the official definition of the pattern and two more "real world" examples: authentication against multiple social networks and working with WordPress meta functions.