Shell Space: Flare, Verm, and Spire

flare W

2

verm D

0.5

spire T

0

This resembles Stephen Wolfram's model of shell growth. However, this is an implementation of a simpler model, due to David Raup and later used by Richard Dawkins in an influential popularization. The idea is that all naturally occurring shells conform to the same basic design, varying only in a limited number of quantifiable ways. In this model, you can specify a shell by setting the flare,

W

(the rate of growth of the spiral), the verm,

D

(the "tightness" of the shell cavity), and the spire,

T

(the rate of creep parallel to the spiral axis).