Originally Posted By: hikermor
Three artfully arranged rocks will get the job done, if you are in a fix. Almost any tin can can be made to work with a little effort.


True, but I can't bet on finding 3 rocks of equal height at any moment. Most abundant natural stuff around me is sand. Lots and lots of sand.
I can bet more on "human-made junk" that is scattered these days in the remotest of areas. Three semi-crushed Pepsi cans maybe.