S5: Ep.11 Jay and Lex have gone back to a factory building in Sector 8 to retrieve Jack who got left behind there when they were attacked earlier.
 
Jay finds the telltale signs that a holographic projector was located here, of the kind Jack believes must have been used to create the many appearances of Zoot throughout the City. He explains to Lex...
Lex—come and see this... think of a tripod with a holographic projector mounted on top. Remember what Jack said, 'it takes three projectors to make one hologram'. A three dimensional image, right... Look, this is where they mounted the first projector...
I'm prepared to believe that such a thing is possible. But we're still talking about a form of optical projection, right? So it would need to be mounted out in the open, on a rooftop maybe. But that's not where they are. They're inside a large industrial building with NO clear view out to anywhere...
Q. How's a projector going to work inside here?