Computer: Display: 3D
Abacus 3D   (+1)  [vote for, against]
Use an electronic abacus array to make 3D models.

This will essentially be an analog device, an XYZ array of variable colored balls on microfine transparent carbon-nanotubes with induction transponders to determine their height. Independently powered, they are shifted up and down to place themselves in the correct position. Animation is out of the question. Can solve Calculus too.
-- Trodden, Feb 25 2003

or you could do this by blowing ping pong balls up glass tubes, or something like this with ping pong balls suspended in columns of air although that would just work for one layer of balls.
-- JesusHChrist, Mar 30 2005

random, halfbakery