Prototype of a 3d volumetric display system uses a block of plastic with some sort of layering inside then a projector underneith that projects in slices of image to generate a 3d display.
Resolution is a bit low since each of the slices is a small sliver of a 1080p image coming from the projector. I also wonder a bit about the geometry there the top part will have more pixels dedicated to it than the bottom due to the angle and also the brightness will likely vary across the image brighter at the bottom than the top due to inverse square.
They have various plans to improve it and this is a developer version not a finished consumer product an interesting idea even if I have some doubts about the technology limitations.