GeomView is a very well written, NSF-funded copyleft 3-D visualization package oriented towards math and geometry researchers. (It is not often the Los Federales fund good copyleft code: If you use this code and send them email telling them so, it will help them maintain the funding to maintain the software. Do it!) Anon-ftp to geom.umn.edu.
Full PD source for all the code in the Graphics Gems series of books is available for anon-ftp at princeton.edu in pub/Graphics/GraphicsGems.
Ygl is a copyleft implementation of (some subset of?) SGI's Graphics Language.
http://www.thp.Uni-Duisburg.DE/Ygl/ReadMe.html.
ftp.thp.Uni-Duisburg.DE (134.91.141.1):
pub/source/X11/Ygl-2.5.tar.{Z|gz}.
EMail: fred@hal6000.Uni-Duisburg.DE.
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