partial torus prims

[Rene Rechthaler]

I would avoid using "inside" and "outside" again, these are already used for the full quarters...
I didnt find any mathematical terms for the main lines of a torus:
https://en.wikipedia.org/wiki/Torus#/med..._torus.png
so I looked for other location terms and found them in the anatomy:
- ventral (belly sided) could be the innermost ring
- dorsal (back sided) could be the outermost ring
- lateral (side) could be the side ring
- medial (center) means to the center
>indexes from inside to outside: v as the innermost, then m medial, l for lateral and d as outermost
>the number as before...

edited the wikipedia pic: