My mom, sister, and I are going to be doing another stitch along in April. They are using the preprinted sampler from Rebecca Ringquist/Dropcloth Samplers (the sequel). I’m going to do mine on the gray polka dots. The first stitch is the guillouche/guilloche stitch.
Guilloche is an architectural term — “an ornamental border former of two or more bands interlaced in such a way as to repeat a rounded design.”
The stitch itself is a composite stitch made up of french knots, stem stitch, and woven running stitches.
I can’t really find a lot of samples of the guilloche stitch in practice — most of what comes up when you search is links to the same couple of tutorials.
In addition to stitching, I splashed some paint around in my sketchbook, just making marks inspired by the stitch.
Once you see examples of what the architectural feature looks like, you’ll probably realize you’ve seen it before, you just didn’t know that’s what it was (I certainly didn’t!). Here’s one picture, but then I’ll also link you to a site that collected a number of examples!