A design pattern is a specific way of solving a particular problem. They are not simply about reusing code; they are more abstract and generalized than that. They are about using reusing ideas.
The Facade Pattern
The best way to understand the facade pattern is to look at a component diagram of a system before and after using a facade.
The next figure shows the front end of a Web site communicating with an application on the Web server. In the right side of the diagram, the front end code is accessing various objects in the application. On the left, showing the facade, the front end communicates only with the facade object, which in turn delegates responsibilities to the internal objects.