I've been following Dynamicland since its inception, and the work is really cool. But it seems like all of the interface work is rather two-dimensional (i.e. using paper). Isn't the underlying theory that this is all based on that humans are better suited at working with three-dimensional objects (like doorknobs and cutlery and what not)?

I think it would be really cool if the Dynamicland UI technology (projection and object recognition) could work with e.g. 3d printed objects, especially if they could be embedded with motion tracking sensors in the case that your hand occludes the computer vision trackers. Is anyone working on that sort of thing?