Using the same OpenSCAD code of kitwallace's from yesterday, today we made a Mobius-like solid whose cross-sections are triangles and whose boundary is the trefoil knot - that is, the knot that wraps three times around the outside of a torus while wrapping twice around its handle.
STL file: http://www.geekhaus.com/makerhome/day168_trefoilmobius.stl
Thingiverse link: http://www.thingiverse.com/make:65700
Settings: MakerWare .3mm/low with the custom knot support described in Day 110.