About this 3D model

This is Day 5 of my collection of printable equations. To see the whole collection, go to: http://www.thingiverse.com/thing:227210 For today's equation, I'm revisiting the Archimede's spiral (r = a*theta) of day #3 (http://www.thingiverse.com/thing:228425). A variant is Fermat's spiral, r = +/-a*theta^0.5 (http://en.wikipedia.org/wiki/Fermat%27s_spiral). In contrast to Archimede's, Fermat's spiral exhibits a flat region near theta = 0 and a continuously decreasing distance between turns. It also, to the best of my knowledge, has no practical application. But it looks cool. Details: - units are in mm - curve thickness was reduced from 5 to 3 mm to avoid overlap. - a = 1.5 (to give a diameter of 100 after 3 turns) - Range(theta) = 0 to 1080 - stl resized to make x axis = 100 mm As always, I'm going to continue to post one equation per day until get bored or people lose interest. If there's a particular equation you'd like to see, leave a comment and I'll give it a shot.