Interlocked Rings

I took guru\'s very cool OpenSCAD file, cleaned it up, made it fully parametric, and fiddled with the parameters.

Specifically, the following parameters are different:
* I made the rings a bit thicker so the build quality is improved.
* The number of rings is now adjustable, and they are arranged in a circle.
* I played with the tilt of the rings and the distance between them so they didn\'t overlap. (necessary, since they are now bigger)
* The *tor* versions have had the cylinder section replaced with a toroid and have been further tweaked.

The ideal offset between rings could probably be calculated, but I don\'t feel like thinking that hard just right now. (Maybe in a future revision.)

I\'ve included here 3 and 7 ring sets. Up to 7 can be made before the first and last rings overlap. The toroid version has been tweaked so that 10 rings can fit and make a complete circle.

Guru\'s original design makes the ring out of a section of a cylinder, and I have left that ver