To honor our radial saint, I’ll walk through the development of a circle-based pattern I’ve been working on as a potential sail design.
In order to work off of the millstone pattern as the basis for a design, I needed to understand how to draw that pattern somewhat accurately. At first, I mistakenly thought the eight “master” furrows were radial, with the shorter furrows parallel to those radii, like this:
But in actuality, the master furrows are more tangential to the inner circle:

The tangential effect rendered here is a little more extreme than on the actual stone, but incorporating it into the design gives a much better sense of it’s character.

Super-imposing five of these semicircles over the area of a sail causes some interesting overlays; some of the furrows are aligned while some of them cross.

If over-printed with a transparent paint or dye, two overlapping colors would combine to create a third color. But maybe this design is a bit too crowded and complex, especially when it’s applied to all four sails:
To see what this pattern would really look like, I’m laying it out full-scale. I folded the fabric first to create guidelines, then drew out the circumferences using a giant compass. Now I’m outlining the furrows with a straight edge.

(It’s hard to see unless you have some dedicated friends to hold it up for you from far away).
Speaking of which, sometimes it’s important to take a big step back, both literally and figuratively. It may be wise to revert to the simpler design of the previous full scale test, as seen here from afar:
and even farther: 