Mirrors? Seems like what you mean is something like a laser hologram,a technology that's been well known by the amusement industry for more than 30 years,where a 3D video is played with help of laser projectors.
If you ever go to places like Kennedy space centre or Disneyland,you can see it work. There is probably even 3D movie halls near your home town that use the technology,often in combination with imax video systems.
What Apple is most likely working on,is virtual reality in 3D,which is a much more portable system,see for example oculus rift or similar VR/AR glasses.