>Dragan,
>
>You forgot: planet, star, sector, galaxy.. *g* and region is needed to separate me from the guy with the same name and street living in Austin Minnesota.

Also in Austin Powers, and Austin Mini (not quite the same as Mini Morris).

I assumed there'd be a universes-level zip code - reality#+universe#+galaxy# + system#.planet# (single byte, until they find a system with too many planets), and then the local takes over. The resulting GUID may be as long as a leg... it would then truly be in the "10 levels or more" province.

>>The most complicated human structure that I know this about - an ocean liner - has ten levels of assembly (i.e. parts which are assembled from parts which are assembled etc). I guess a space shuttle or a Mars vehicle may have an equally deep tree structure, maybe 12 levels, but I doubt that - each level has to have something that's physically containing smaller parts. Just folding paper ten times gives you a piece that's 1024 times thicker than the original. Even an absolute address of a person may not go beyond that - country, region, city, street address, person's name - that's five levels, and the region can be actually skipped. Going deeper, you may want to address each individual cell of his body, you may need few levels more (organ, tissue, cell ID). And that's it - unless you want to address an individual atom in the known universe.