This pattern can be completed in any weight yarn and at any gauge, though the finished measurements and total yardage will vary significantly.
Inscribed angles, excircles, 9-point circles… The relationship between triangles and circles is a complex one, but the geometry of this garter-stitch cowl is decidedly simple. If you take two identical triangles, invert one and join them, you get a parallelogram, and a parallelogram with its sides connected is a loop. Put another way, this cowl starts as a top-down triangular shawl. Then, when half the yarn has been used up, you connect the two outer points of the shawl, and use the live stitches to knit a bottom-up triangular shawl. You end up knitting the entire loop flat, only casting on and binding off a tiny number of stitches. Magic!
Using one skein, the cowl creates a lovely little pop of color and warmth around your neck. With two skeins, it’s big enough to loop twice, to wear around your shoulders, or to cover your ears while keeping your neck warm. It’s a particularly good way to show off ombré and slow-color-change yarns. Simpler than it sounds, Arccos takes a new angle on knitting loops!