GLE, written by Linas Vepstas, 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. OpenGL is used to perform the actual rendering. GLE is also included with the latest release of Mark Kilgard's GLUT toolkit.