GLE is a library package of C functions that draw extruded surfaces,
including surfaces of revolution, sweeps, tubes, polycones,
polycylinders and helicoids.  Generically, the extruded surface is
specified with a 2D polyline that is extruded along a 3D path.  A local
coordinate system allows for additional flexibility in the primitives
drawn.  Extrusions may be texture mapped in a variety of ways.  The GLE
library generates 3D triangle coordinates, lighting normal vectors and
texture coordinates as output. GLE uses the GL or OpenGL(R) API's to
perform the actual rendering.