pattern courtesy Yarn Harlot:

(PS. Because someone will ask, and even though I swear you don’t need a pattern, here goes. Using worsted weight cotton and 4.5mm needles, cast on some stitches. I use about 30-35, but this one is 31. Choose a stitch pattern you like. This one is Bee Stitch, but you can do ANYTHING. Whatever goes in the middle, I like garter stitch borders, because I like them nice and square and finished looking. I knit six rows, then keep the first and last three stitches in garter throughout. Knit until it’s just about a square, then knit six rows. Cast off. Glory in the useful thing you have wrought. Ignore naysayers. They don’t understand how useful your skills are going to be after the zombie apocalypse. They’ll be washing their faces with rags and leaves while begging us for a washcloth. We will be as Gods.)