The basis of technology is a small hand-held projector with a positioning system in space. Hotaru (firefly in Japanese) allows you to use any surface as a virtual desktop. Moreover, fully three-dimensional, because You can "light" all the surfaces around the user. The device "highlights" a certain part of the virtual space.
Develop a device to virtual points + - we get a complete overlay of virtual space on the real world. Very similar to the virtual desktop, which was used by the anime characters Ghost in The Shell. Only there the virtual space was projected directly into the brain. But this, IMHO, too ...