I had something slightly more ambitious in mind, but it was taking too long, so I quit here.
The first few (dozen) times I tried the round embroidery stitch called a French knot, my stitches knotted too soon, and they looked like crap. Then I managed to do a couple clean, and felt like I’d gotten it.
So I ripped out all my failed stitches and tried French knots in 5 different sizes … in these breaking waves. Yay!