Converting the interfaces in hierarchical structure in OOD

I have a question about Facade design pattern. As i started learning design patterns from the book: Elements of re-useable object -oriented-software, there is a good explaination of what it is and how it solves the problem.

This Picture comes from that book:

Problem: Suppose i add some extra functionality in the subsystem for which Domain is an Facade/interface. With this design, i think it's not possible to add extra functionality in the subsystem without changing the Domain class?

Second, suppose i use an abstract class Domain(to create a hierarchical structure) and delegate all the requests to it's subclasses so that whenever i want to add new functionality , i simply extend my new class/subsystem with Domain(abstract), would that be wrong or still i will have a Facade structure?

Same thing happends in Adapter pattern. We can have different kind of adapter and instead of hard-coding one class , can we create such an hierarchial structure without violating any OOD rule?