The application runs under Windows XP and should run under Windows 98.
You might want to use the Windows command-line interface (used to be
called DOS) to rename them:
ren rhombic.xxx rhombic.exe
ren rhombic.zzz rhombic.chm
The reason they have been given names ending in .xxx and .zzz is that
many or most Web browsers will not allow you to download an .exe file,
for security reasons.
Here are the files:
The rhombic executable
The Help file
Please email me if any problems "installing" or running the program: wn1z.orrin@gmail.com