Business: Advertising: Media: Billboard
Spitball Billboard   (+6)  [vote for, against]
Computer controlled spitball cannon "paints" picture on wall.

This display uses a computer aimed pneumatic spitball cannon which "paints" a picture out of colored spitballs. The "spitballs" are actually reusable clumps of fabric which are soaked and compressed by a muzzle-loading piston ram.

The display can be wiped clear with a water hose, so the next image can be painted.
-- IJK, Mar 27 2007

If it wipes off with water, then wouldn't they dissolve in the rain? I suggest some adhesive that breaks down when subjected to catalitic levels of alcohol or bleach or something. And I dont think the spitballs need to be reusable...

Could make some really cool murals too.
-- Smurfsahoy, Mar 27 2007

The only really practical way to make this display work in the rain would be to use an entirely different mechanism for the "sticking"--like magnets or lots of spikes or velcro. That would be a different concept, of course, and would perhaps be less amusing for the market audience to watch.
-- IJK, Mar 27 2007

This is a great idea. As described, it seems mostly about displaying 2D images, but I think it also presents an interesting opportunity for displaying in 3D. You could build up bas-relief sculptures with considerable depth if you waited for each layer to solidify before building up another layer. (The "spit" would probably need to contain plaster or a glue if you really wanted to build up sculpture this way.)
-- lankybits, Mar 27 2007

random, halfbakery