(Edited November 17, 2014)
I use Daniel L. Isdell’s Celtic knot font to design my Celtic knots.
I use MS WordArt to warp them into circles.
I am posting a series of pages showing open-ended Celtic knot sections and the resulting circular Celtic knots.
I will color Celtic knots with multiple cords accordingly. The blank knots consist of a single cord.
The knots shown below come from two knot sections stacked on top of each other.