In order for the viewer to perceive the head of the virtual person in Figure 4, some photons must enter the viewer’s eyes coming from the direction of the head, along the red line. But where do those photons come from? If they come from the “holographic projector” at the right, then they must have changed direction in mid-flight somehow. Photons don’t do that unless they bounce off something solid, and thin air won’t qualify (and a fog-screen display is decidedly not what the Kickstarter project promises). The only possible source for photons entering the viewer’s eyes from the required direction is a light source behind (or in front of) the virtual person, anywhere along the red line. Like, for example, a big fat life-size screen behind the object. In other words, a CAVE. Or two small screens right in front of the viewer’s eyes. In other words, an Oculus Rift. With the setup in Figure 4, the only part of the virtual person the viewer will actually see (indicated by solid color) is its intersection with the pyramid formed by the screen rectangle and the pupil. The rest simply won’t be there. If that part is all you want to see anyway, fair enough, but that’s just you.