This web address is meant to serve as a "private platform" for data exchange and data backup. No commercial intentions. Since  2004 the pages also illustrates some of the work of Jürgen Bonhagen (e.g. visual arts and developments for a very interesting computer game). People who like brain-challenging (and well - designed) "logic puzzles" should have a look at his special Rocks'n'Diamonds" (R&D) site.