I’ll be building something along the lines of the second sketch.  Basically, a small piece of plastic (diffraction grating) moves in x-y via joystick- between two crossed polarizers, creating a transparent window to a scene behind it (see sketch 2).  The movement of the window is done by a pulley system inspired in part by printers- the servos are mobile, moving along tracks.  Polarizers are glued between glass, everything is taking place between the glass :
photo-2I collect scrap plate glass- the cleanest stuff I have are these 2’x1′ pieces.  I’d should probably cut them down, but thanks to american science and surplus I can at least afford a lot of polarizing material.  We’ll see how this goes…