Shell 2

This larger shell is another form which shows the power of mathematics in reflecting the laws of nature. The opening here is perpendicular to the direction of growth. The organism always needs a similarly shaped home as it grows, which is modeled by an exponential spiral that expands at the same rate that it drops and moves out from the central axis. . This shell was created in Mathematica using the formulas developed by Deborah Fowler et al (Siggraph '92). It was cleaned and solidified in Meshlab, touched up with Netfabb Cloud. The mesh was created by a routine which perforates the polygons to a minimum width; their edges were thickened by the Meshlab "marching cubes" algorithm. It is printable in white or colored plastic, and metals which accept a .9mm minimum dimension (raw brass, bronze, and silver. Contact me if interested either in the mathematics or in a model printable in other materials.