How can I use gh to create this kind of helix?

[blackpepper (greenmustard11)]

[martinsiegrist]

Did you take this object apart in your head? Would you know how to model it in Rhino?

[laurent_delrieu]

Hello
I see an helix curve with radius changing along the axis. As the change is quite continuous I’ll take a

Radius(t) = RadiusMin + (1+sin(A t))(RadiusMax - RadiusMin)/2

Helix Spiral from Nautilus plugin or elsewhere

But if you want a constant slope, I think you’ll have to make your own tool.

[blackpepper (greenmustard11)]

WOW,Thank you so much!

[saeed_hasan_zadeh (saeed)]

wonder if someone know name of such spiral type?
or it is just repeated of mirrored half Archimedean ?