Looks very accurate !  
Tough I didn't see the code, I have a suggestion : add a parameter
that allow to choose between :
- real spiral(as you did), for when the thing is viewed close
- false spiral, made from a stack of cones, for when viewed farther
- no spiral at all, when it is not visible.

the last two options would allow less memory consumption and parse time.

Cheers,
Fabien.

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