This is a tool I wrote to explore parametric surfaces of
two parameters (u and v, hence the name).

You give it the equations X(u,v),Y(u,v) and Z(u,v), and the
limits and increments for u and v, and it computes and 
displays the surface described.

You can then rotate and illuminate and render the surface
in various ways. This section is all done w/ integer math,
and is just about as near to realtime as its going to get---
typically <10 secs redisplay time for 10,000 verticies
using the slowest display mode (the nebula mode or an
edged solid mode) on a plain 7.14 MHz 68000 Amiga.

And you can also save images of the surface, and (3-D MODELERS TAKE
NOTE!) the surfaces themselves as TDDD 3-d objects.

This one runs under 1.2 and 1.3 w/ arp, or under 2.04 without.

 PERMSSN    UID  GID    PACKED    SIZE  RATIO     CRC       STAMP          NAME
---------- ----------- ------- ------- ------ ---------- ------------ -------------
[generic]                  786    3046  25.8% -lh5- caa2 Sep 12  1992 NiceEquations.txt
[generic]                10587   17452  60.7% -lh5- 0e60 Sep 18  1992 uvSurf
[generic]                 3308    7729  42.8% -lh5- ffdf Sep 14  1992 uvSurf.doc
[generic]                  574    1260  45.6% -lh5- 1f60 Aug 29  1992 uvSurf.info
---------- ----------- ------- ------- ------ ---------- ------------ -------------
 Total         4 files   15255   29487  51.7%            Feb  3  1993