Helix - Banana Yoshimoto

I read this stroy and found it as a nice story. One of the words that I am eager to know in the story is 'Helix'. According to my research:

A helix is derived from the Greek word. It is a twisted shape like a string. Helices are important in biology, as DNAi s helical and many proteins have helical substructures, known as alpha helices.

In geometry, helix is the curve formed by a straight line drawn on a plane when that plane is wrapped around a cylindrical surface of any kind, esp. a right circular cylinder, as the curve of a screw. Equation: x = a sinθ, y = a cosθ, z = b θ.

In Anatomy, helix is the curved fold forming most of the rim of the external ear.

Source: http://en.wikipedia.org/wiki/Helix