| 23.12.2003: | Seasons Greatings 2003 |
| Some changes not listed | |
| 19.12.2001: | Finally: XMAS 2001. |
| 4.4.2001: | Learn to fight.. |
| 15.2.2001: | If it was good for J.J. Rousseau it might be good for us too. |
| 19.12.2000: | Christmas 2000 - last Xmas in this millenium | 18.11.2000: | Math and Movies |
| 14.11.2000: | Pedagogics |
| 4.4.2000: | I have seriously started to wait for Easter |
| 14.12.1999: | More ideas about a truely modern university |
| 11.12.1999: | I have seriously started to wait for XMAS |
| 2.12.1999: | Added a Guestbook |
| 29.11.1999: | Fighting against widely spread lies |
| 22.11.1999: | Today I received this email |
| 20.10.1999: | An old man's wisdom |
| 26.6.1999: | Fixed the link to the Popocatépetl |
| 24.6.1999: | Good News again: Germany has become a normal country |
| 3.5.1999: | We really must try harder |
| 9.2.1999: | Tranferred the homepage of the Seminar Sophus Lie to Hans Joachim Hilgert in Clausthal. |
| 27.1.1999: | Some links added |
| 8.1.1999: | Added an impressive portrait of the autor |
| 18.8.1998: | A truly inspiring page made by an artist: Postmutant Eggplant |
| 1.7.1998: | I wish I would stand at the foot of the Popocatépetl |
| 20.5.1998: | After so many weeks a new Feature of the Week |
| 8.4.1998: | Added some encouragement to study mathematics: moved outdated pages to the archive. |
| 8.4.1998: | Added a link to the most impressive page |
| 7.4.1998: | Updated Good News |
| 25.3.1998: | Minor reorganization of the homepage; |
| moved Xmas calendar to archive. | |
| 25.3.1998: | Installed this page. |
| 24.3.1998: | Added a link to a Webcam in Frankfurt/M. |