nautilus windmill - customizable

Notes:
- There is a [newer design](https://www.thingiverse.com/thing:902703) of this.
- tested with OpenSCAD 2021.1

For experimenting it's better to have a customizable version.
Too many windings increase drag. So, to bring in a new aspect I used a logarithmic spiral instead of the Archimedes spiral shown [here](https://www.youtube.com/watch?v=i6QyBdPGbFE).

Notes:
- CGAL rendering is not very fast.
- Cut the foot off after print to enhance aerodynamics
- Let me know your results.