A simple primitive based on a logarithmic spiral.
This is an old work in progress I never finished. The Creation Method and Mapping Options rollouts are just placeholders.
The geometry part is functional, though.
The plugin creates a new Snail primitive that appears under the Special Primitives category in the drop-down list.
Hopefully, the parameters should be self-explanatory.
Paste the code in a new script window and evaluate it (you might have to do it twice, for some reason).
The new Special Primitives category should now appear in the list with the Snail primitive.
If you want to keep it permanently, you have to save the script in one of max's startup folders.