The tabletop projection interaction is nearly a trope at this point, but Kollision's Tangible 3D Tabletop adds some interactions that I found new and useful. The idea of treating a plane as a viewport for a map is a fairly natural interaction. I think the perpendicular nature of the plane could still use some tuning, but the execution is pretty incredible. I can imagine this interaction being used in the reverse--a block representing a section line moving across an image of a brain and show MRI slices for instance. The attractive part of this interaction is that it breaks the keyboard, mouse, screen paradigm. It also manages to stay in reality, unlike VR for instance. I think this technology could have strong use in educational environments.

Link to project.