You don’t often see a cowl in a triangular shape, I love the idea! I think this cowl will also be a lot of fun to crochet, because of the alternating rows. This pattern uses worsted (4) weight acrylic yarn and a 6.0 + 6.5 mm crochet hook.
You can find the free crochet pattern of the Bauble Bandana Cowl on the website of I Need it Crochet.
Related tutorials: How to crochet the bead stitch.