I would like to make a low resolution mirror using sand and air. There will be a container of sand above an X/Y grid of holes. From a long slot opening downward from the bottom of the container, the sand will fall in front of the holes which push and pull small currents of air in and out.
By moving the sand in the Z space as it falls downward, the mirror will give the impression of a 3-D image moving. One particular feature is that sand will constantly be flowing downward, giving the illusion of an image that is “alive”. This could also be done with some piece of thin fabric as in this video.
Another option I found besides programmable air is using fans like these. This way, I would not have to worry about the programmable air and its noisy system and I could make a network of fans. Computer fans also come to mind. They are usually slow, cheap, and I can flip the phase of the power to have them flow in the opposite direction. So that is a better sounding option to me. Below is a drawing of what I have so far.