On Fri, 7 Jul 1995, David wrote:

> I would like to have a map, that with a press of a button, will show  a
> lava flow, then an ice flow, and a flood area.  These three areas would be
> show their flows over the same map.  I was thinking about fiber optics,
> but there must be other ways to do this...  It would be nice if each of
> the flows could be a solid color.  It seems to me that I have seem someone
> do this with different layes of glass, and was able to light up each
> one...    Anyone done this before?

Years ago, we did this with lines by routing the regions into layers of
plexiglass.  When you feed light into the plex along one edge, the lines
glow.  The biggest problem we had was to prevent light leaks into the
other sheets.

Depending on how your exhibit is set up, it could also possibly be done
with rear projection in a shadow box.

-jesse