
The demos are best seen in order, from the most basic, to the advanced. 
Run the "rundemo" script.

Note that most of the demo's were written using cut & paste, starting
with the simplest demo, cylinder.c.  We could have written a fancy demo
package that avoided all of the cut&paste of code, but we felt that this
would only hide what we are trying to show here: the programming API for
the tube & extrusion library.
