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 = atheta) of day #3 (http://www.thingiverse.com/thing:228425). A variant is Fermat's spiral, r = +/-atheta^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: 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. All files can be printed without support. Photos shown were printed on a Replicator 2 and sliced using the standard setting on Makerware.