Here's a bit of an experiment. To simplify measurements, I placed alternating marks every 2mm and 4mm, and then drew my guide lines at a 45 degree angle. A T square and triangle made things easy going. Only thing now is that want to get into breaks and corners. For that, I need to fall back to Katharine's web site and my book. So, for now, I'm off for a bit of research. I'll be back tomorrow ready to try out some fancy knotwork. :-)
And here's another peek at nature's try at a little knotwork.