polyhedral crystal display

This 3-D (like a window) display has a huge array of many, many, many tiny lasers behind it. Here's how it works:

Each crystal on the surface will vector light in many, predictable directions depending on where the light is coming from. To show a 2-D display one would shine light such that all of each pixel/crystal have the same color on all facets. To show a 3-D display, like a window, the color shown on facets the same direction show one image. A facet, say, half a degree off show a slightly different image.

By refracting three lasers in each facet of each crystal you'll have a clear, bright, three dimensional display.