Kahlen was a founding member of the Video-Forum, which opened with his work Reversible Prozesse. For his installation S.C.H.A.F.E., the performance artist, object artist, and media artist had a herd of sheep form the individual letters of the words Schafe (sheep), only to dissolve when the animals disperse. The images are accompanied by the sheep bleating and by voices commenting on the action during production. The single screen video is a variant of the work conceived for six monitors.
- Reversible Prozesse (n.b.k. Koproduktion)