ZIP-method: 

The name " ZIP method " was selected for the new kind of solution, because every round trip
has to be divided and reassembled like a zipper into two equally large subsets.

By the way of the ZIP method it is possible to reduce the number of all round trips to a minimum
of basic forms. The calculation of these basic forms and there consecutive recombination into
new round trips will only require a minimum of work as compared to an overall calculation of all 
round trips.