Secondly, what are the differences between a 3D-2D and a 2D-2D interface? And thirdly, how you might control it -- is there a way to deliberately design the interfacial structure" to produce ...

Once you start overlaying 2D and 3D objects over reality ... at each side of your head and having the (semi) transparent visor reflect those images to your eyes. If this is the case, it will ...