Author: Alexey Voronin a_voronin (at) list.ru

This is Archimedes screw that can work without surrounding pipe.
It is divided in sections so that it can be put on some central pole.
You can also print it withous outer wall and have an auger.
It can be printed without support!
But single vertical screw is liable to fall sideways.
So print at least matrix of 2 x 2.