Idea of the day - magnetic mental marbles

Ok, time for a little more off-beat idea. Imagine if you could take the technology that exists now for quadraplegics - which allows them to do things like move a cursor on the screen, etc. etc. and apply this to a "toy" Imagine you have say 10 - 20 marbles which each have within them a little reciever. You have a headband or something which translates your intentions to each of these "marbles" individually. Each marble could be Positive, Negative, or Off in terms of magnetic (or have sides that could switch). Then , using just your thoughts you move the little balls around the table - pushing and pulling against one another. You might even get good enough to get the arrangement of small shapes or figures - somewhat like those office toys you see where you can "stack" little magnetic pieces of metal.

Anyway - it seems like it could be a feasable thing, and might be quite fun to try to create.