At 21:15 30.09.00 +0200, I wrote: >I drew a sketch of such a thing, I've put it up to: >http://www.uni-bonn.de/~uzs159/tubelad.gif Whoops, that one is broken and I have trouble accessing it, so please use http://members.nbci.com/rene_schmitz/tubelad.gif Sorry, René -- uzs159 at uni-bonn.de http://www.uni-bonn.de/~uzs159