Very OT: good geometrical optics shareware ?

[Haible Juergen]

Sorry for the OT post.
Please reply with private mail to
juergen.haible at nbgm.siemens.de

Does anybody know a good shareware program
to design a simple optical system with mirrors ?

No complicated stuff requred, really, but the program
should be fairly comfortable, graphical user interface,
Windows NT.

Any idea ?

Thanks,

JH.