retired and busy with detecting what I want to learn and know, like doing mathematics, visiting the Berlin planetarium, attending astronomical workshops or lectures at the universities, reading books, watching movies, in particular at the international film festival Berlinale, traveling to somewhere, seeing friends, hearing concerts in the philharmony, go swimming, go biking along the Teltow channel, practicing Qi-Gong and Taiji, and since 2007 sailing on Berlin rivers.