Thanks for this. Now I'm trying to think of ways that you could actuate thin metal rods, so that you could transform a greyscale picture into a sort of texture-photograph, so that you could "see" details by placing a hand atop it. If the rods are needle-thin you could probably get a reasonable resolution on it, and even have some brightness/contrast sliders on the side to help -- but it seems like the real problem is just moving all of those little rods automatically.