In early 2013 I discovered pico-projectors. I picked up a relatively inexpensive one (Microvision SHOWWX+ with HDMI input), which sadly can no longer be purchased! It was an incredible piece of technology, which is/was ahead of its time. The first application I came up with it was to create a water vapor display. Basically, generate water vapor (fog), blow it into a curtain with laminar flow, and project an image on it. I created a manifold of about 20 channels, with two plastic bag air-resevoirs (to 'still' the air), pressurized by 2 CPU fans. The manifold had a gap at the based through which water vapor could be sucked up and lifted into a curtain. After building the whole thing, well, it didn't really work. I couldn't get enough fog up into a curtain.