Yet another project inspired by nature and once again it is the sea to offer me the subject.
In this personal experiment I studied the forms of ammonites, an extinct group of marine invertebrate animals.
Ammonites are excellent index fossils, and their fossil shells usually take the form of planispirals, although there were some helically spiraled and nonspiraled forms.
The name of an ammonite genus ends in -ceras, which is Greek (κέρας) for "horn".
http://en.wikipedia.org/wiki/Ammonoidea
