GPLconx is in the pre-alpha stage.  Use at your own risk.

GPLconx is a visualization tool that provides interactive visualization of
points, lines, circles, ellipses, hyperbolas, parabolas, and equidistant
curves in three models of the hyperbolic geometry of two dimensions,
the Poincare Upper Half Plane, the Poincare Disk, and the Beltrami-Klein Disk.

Such visualization is helpful when you are trying to appreciate the
implications of replacing Euclid's Fifth Postulate with the idea that,
``A line A can have two distinct parallel lines C and D that go through a
point D not lying on A.''  Although this may be the true geometry of our part
of the cosmos, it is not the geometry that most of us learn in high school.
Playing with conic sections in GPLconx will expand your mathematical horizons.
Every geometry student should have the chance to interact with hyperbolic
geometry.

Currently, GPLconx is written in C and C++ and has both a Tcl/Tk GUI
(with widgets built with SpecTcl 1.1) and a GLUT GUI that enhance the
visualization, which is done in OpenGL.  It uses GNU Autoconf and GNU
Automake for configuration, and should run on any Un*x or GNU/Linux system.
A Java port is in the works.  A 3-D version is desired,
since there exist models that put all of space inside a unit sphere.  This
is great for representing a universe of data, such as the World Wide Web,
and has also been used to great effect as eye candy for electronica.

In short, GPLconx exists because postulates are not as hands-on for most
people as a GUI.

The user interface and language are changing so that more students can
have access to GPLconx.

GPLconx is released under the GNU General Public License.  See the file
`COPYING' for details.

Togl, found in `Togl/', is released under its own license.  See `Togl/README'
for more.

SpecTcl 1.1 is used to engineer the `src/*.ui' which become the
`src/*.ui.tcl'.

You can find GPLconx on the web at `http://gplconx.sourceforge.net'.  There
are two mailing lists of general interest, gplconx-users and
gplconx-announce.

To install, you can usually just edit `src/Makefile.inc' and tell where
to find your libGL, libGLU, libtcl, libtk, etc. and then run
`/bin/sh ./configure; make all install'.  The only non-standard package
you need is `lcl-0.3', the Linux Class Library, but the subset of it that
we use (which is not Linux-specific) is in `src/lcl' and is configured
automatically.

Before running `make', you can edit `config.h' to change a few things that
make little difference (unless you run into trouble later).  More instructions
on installation can be found in `INSTALL'.

There is Texinfo documentation in `doc/', but it is only a start. DLC

See `AUTHOR', `NEWS', `THANKS', `TODO', `README.DEV', `LICENSE', `INSTALL'
and `COPYING' for more information.