Solid Geometry

Geometry Machine - 3D virtual reality geometrical images of vectors, lines and planes. Needs a VRML viewer or plugin such as live3D.
www.scit.wlv.ac.uk/~cm1993/geometry/INTRO.HTM

The Geometry of the Sphere - This material was the text for part of the Advanced Mathematics course in the High School Teachers Program at the IAS/Park City Mathematics Institute at the Institute for Advanced Study during July of 1996.
math.rice.edu/~pcmi/sphere/