Pencil holder/cup designed in OpenSCAD using celtic knots from Wikipedia (http://commons.wikimedia.org/wiki/File:Quasi-Celtic-ornamental-knot-49crossings-inrectangle.svg) and the capital J from a freely available rune font.

Printed at 75% scale and 5% fill, turned out great with the exception of the bottom for some reason had a slight offset. Support is not necessary and really shouldn't be used because it's super annoying to cut off (initial attempt used supports).