I don't understand why a command pattern is convenient in object oriented design?

Your Switchable creates an abstraction between invoker and receiver but they are still coupled (invoker has needs a reference to the receiver). The Command pattern lets you create that decoupling. The invoker says to some intermediate component "hey I've got this command I'd like to be executed" and then the intermediate thing can dynamically pass that request on to the receiver.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.