At OFSET - Case studies - Dr. Geo [1]
OFSET - www.ofset.org
A DYNAMIC GEOMETRY SOFTWARE
http://www.ofset.org/drgeo

A software engineering project
Contributions are:
translations
documentation
example files
scripts
a few patches
Incubated at various places
Source code at Gnome CVS
Web site, documentation and mailing list at OFSET