A Napkin

Even simple parametrizations can be beautiful. Here is a Napkin. It is the surface
r(s,t)=[t sin(s), t cos(s), t+s]
The following pictures were generated with Mathematica in such a way that it can be printed. For more, see the work of Elizabeth Slavkovsky on 3D printing in the classroom. An article is contained in this free book on low cost 3D printing. There is also an extended version with more code (on the ArXiv, one can download the LaTeX source code).