This is the history of the Light++ raytracing library:

12.01.1991: First two-dimensional trials of the raytracing algorithm with use of base classes, multiple inheritance and virtual functions.
01.06.1991: Generalization to three-dimensional raytracing.
05.04.1991: Rewriting of some Turbo-Pascal Code concerning gourod-shading and wireframe-modeling from the magazine C't into C++.
21.03.1992: Acceptable gourod-shading with Phong-lighting and Z-buffer under GNU C++ 2.2.2 (DOS).
17.05.1992: First simple simulation of a gravitational lens by spherical approximation of the ray path. These simulation have been presented in July during a Summer School of the Austrian Space Agency in Alpbach (nice, tiny village in Tyrol).
17.08.1992: Some fascinating ideas have been found in the code of the raytracer DBW_Render.
20.03.1993: Simulation of a gravitational lens using the exact solution of a timelike geodesic in the Schwarzschild field.
01.01.1994: Implementation of the Radiation Transfer Equation for a realistic description of interior light.
03.10.1994: Creation of the Internet WWW Pages
Feb.1995: Creation of the Cloud Web Pages
Sep.1995: Publication of the Cloud Program in the November/December Issue of Computer Grafica (Article by Stefano Alberico) and the Black Hole Simulation in Relativity and Scientific Computing - Computer Algebra, Numerics, Visualization, Springer Verlag
10.12.1995: Public Release of the Source Code (sorry, no longer available on math1).
09.01.1996: Searoses Simulation and (Animation)
20.04.1996: Starfield Simulation (Globular Cluster)
16.08.1996: Moving objects, parallel raytracing for animations
23.08.1996: Raytracing of the SAO Star Catalogue
01.09.1996: The Clouds Generation Tutorial
23.09.1996: Implementation of new fractal cloud algorithm
25.09.1996: Raytracing Animation of the Pseudo-Escher Cube (not exactly the true Escher Cube)
21.07.1997: The Black Earth - general relativistic simulation of the Earth's surface if it were a black hole, including effects of the Photon Orbit
Eastern 2000: Extensive Class Documentation available, the source code of the Light++ library (kernel) is beeing made available via CVS.
May 2000: Demo Testsuite, which runs weekly to check the functionality of the code, and to compare performance on a growing variety of platforms.
October 2000: Release of the Terrestrian Generator Linux binary
(sorry, if the history ends here, this is not because the work has stopped, but because of lack of time - the library still is beeing used and developed much further!)