Q:

Does a Class extended from a Base which uses an Interface ever need to also use the same Interface? 

This questions comes from my AS3 history, but I think the concept applies to all languages.   I can't go back to check the original code but it has been bothering me for a while and would appreciate some clarity. 
I was tasked with writing a game, MyGame, that extended a GameBase class.   The template I had been told to follow required that the game use an IGame interface, but I found that that the GameBase class also used that same interface. 
Lacking proper notation, I think about it like this:
   MyGame : GameBase
     |          |
   IGame      IGame

This looks redundant to me and I want to know whether it was or whether I misunderstood inheritance in this context. 

A:

The sub class inherits all super types, that includes the interfaces.  There's no need to implement that interface again, because it is already implemented.