Spirals in Nature

low pressure spiral
Low pressure system over Iceland. Image from NASA, taken on . image source

Cyclones in general have the shape of equiangular spiral.

nautilus shell
A cut-away view of the Nautilus shell. Photo by “Chris 73”. image source

In general, Spiral-shaped growths in nature are mathematicaly equiangular spirals.

A garden snail, showing equiangular spiral.

More photos of seashells at Beautiful Seashells Exhibition.

Broccoli Romanesco
Romanesco broccoli, exhibiting equiangular spiral and fractal geometry. 2048×1536 Photo courtesy of Dror Bar-Natan.
Hawaiian fern; spiral
A Hawaiian ferm, exhibiting Archimedes' Spiral. (photos courtesy of Dror Bar-Natan)

Man-Made Spirals

Samarra mosque
Great Mosque of Samarra, exhibiting Archimedean Spiral.
violin neck scroll volute
The neck of a unfinished violin. image source

Such a spiral in ornament is called a volute.

See Also

Mathematics of Seashell Shapes.

Archimedes' spiral, Clothoid, Lituus, equiangular spiral.