Here are a few Celtic crosses for decorating your things. The original images are from here I followed the method of turning 2D images to 3D here This is hopefully just a taste for what we are in for for Celtic decorative knotwork of jjk gets his geometric Celtic generator working - see http://www.thingiverse.com/thing:2596Merge with your things for decoration or print as stand alone objects. If you try to print the complex cross as a stand alone object you will still need to add it to a base as there are non-attached components.