Here is a paper on it: Study of shell shapes
And a good thread with tools: [SOLVED] Creating sea shell
Thank you for your reply. Having Scott Davidson is my honour. Your grasshopper is genius. what do you think how to use grasshopper to make sea urchin shell like in this picture?
Looks like circle packing with fractal spirals. https://www.grasshopper3d.com/m/photo?id=2985220%3APhoto%3A690099&context=latest