You are at it again, from magnetic blades to now sliding weights.
Are you sure you moved to Switzerland and was not run off, to hide/escape?
Anyway the idea of sliding weights is a good one, while I have little to add to this subject I do think a distance related subject might be of interest to you and others and that is; Atlatls and banner stones used with them. I have found these banner stones in years past and this is just two web sites on their use. http://donsmaps.com/atlatl.html
To me a very interesting subject you have started Mr. Jens