Ravelry: 1 Sock 2 Sock Red Sock Blue Sock pattern by The Chilly Dog
Amazon.com: Knit 2 Socks in 1: Discover the Easy Magic of Turning One Long Sock into a Pair! Choose from 21 Original Designs, in All Sizes: 9781635864076: Talley, Safiyyah, Sloan, Jeanette: Books
Pack of 2 pairs of men's finely ribbed lisle mid calf socks in plain blue