I'd argue multi-boxing, and in fact multi-tasking, while initially difficult, leads to the concept of multiple focuses being a single focus with proper, for lack of a better word, processing resources being used in the execution of a task. People always tell me "I have no idea how you can operate ten computers at once." It's not hard, you just have to approach it as a single system. Its not really any different from driving. You have to pay attention to the cars around you and your surroundings, and your actions and reactions are more or less pre-programmed to behave in the manner that people would call "driving a car".
Of course, there is also a great deal of preparation involved and such things tend to require an intimate knowledge of all the processes involved.