This page is quite old. Go here for the latest versions of jhex and jtwixt.
The archives contain (1) the Jtwixt Twixt game analyzer program, (2) a small library of 24x24 Twixt games (file twixt_lib_1.tgt), and (3) documentation.
[The following is for Windows. I assume that Unix users are clever enough to adapt the instructions to their platform.]
(1) Unzip the archive. There should be a files named Jtwixt.jar, twixt_lib_1.tgt), README_twixt.html and other documentation files.
(2) Install Sun's Java Runtime Environment. I recommend the latest version (1.3), which can be found here. (Earlier versions, like 1.1.8, also work, but that's not guaranteed for the future.)
(3) If you installed Java 1.3, you should be able to double-click on the Jtwixt.jar file. For Java 1.1.8, run the command line "jre -cp C:\some_folder_names\Jtwixt.jar TwixtGameTreeApp", where "C:\some_folder_names\ " is replaced with a full or relative path name to the Jtwixt.jar file.
On a Mac:
(1) Unstuff the archive (you'll need Stuffit version 5 or higher). There should be a files named Jtwixt.jar, Jtwixt (the Jtwixt application), twixt_lib_1.tgt), README_twixt.html and other documentation files.
(2) Make sure you have MRJ (Macintosh Runtime for Java) 2.2 or higher installed.
(3) Run the Jtwixt application (double-click it).
If anyone is interested in working on the library, please let me know.
I work on a Macintosh, so there may be some glitches getting things to run on Windows or Unix. If you have problems, let me know and I may be able to help.