For Supercomputing, '93 , Randy and Charlie Gunn developed GeomCAVE , one of the first tools to enable mathematicians take `field trips'. GeomCAVE combines tools developed at the Geometry Center with the CAVE virtual reality system to allow mathematicians to navigate within 3d manifolds and orbifolds, specifically those that can be modeled on three of the eight 3d `Thurston Geometries' -- spherical, euclidean or hyperbolic. See, also, the paper presented at the 1995 Symposium on Interactive 3D Graphics .