Okay, I am totally digging Mario jumping around doing platforming on my desk. I likey. But there are some technical issues which someone very smart has to figure out, mainly having to do with environment recognition and the AR cards.
It's probably obvious to a hell of a lot of people just how the AR cards work, at least in a general non-technical sense. They're a visual marker for the 3DS. Since the 3DS is programmed with the actual dimensions of the AR cards and knows exactly what they look like, it sees the AR card and can pretty accurately guess how far away the card is, because the 3DS knows exactly how large the darn thing is supposed to appear.
But it gets better. The way it accurately deforms your tables and makes a hole in it and makes dragons appear is by knowing what the cards look like when staring straight at 'em, so if they're tilted at a certain angle, the 3DS knows what the angle of the desk is that the AR card is sitting on. So now it can pretty accurately recognize an object in the environment, enough to make Mario stand on top of it believably. Pretty brilliant.
But to make Mario run and jump? I think to do this, you would need multiple AR cards. You would need four (maybe?), 1 for each corner or each side of the desk, depending on how its designed. But what about objects on the desk, like a book or a box for Mario to jump on top of? I'm guessing you would need an AR card up on top of that too, to designate that surface.
You can see where this would lead. You would have AR cards strewn everything to make a sizeable surface for Mario to work with.
Someone smarter, can you think of a more elegant method?