Shown with a cast-on count of 46 stitches.  

• Rows 1, 3, 5, 9, 11, 13, 17, 19, 21, 25, 27, and 29 (RS): K1, sl1 wyif, *p2, k18, repeat from * to last 4 sts, p2, k1, sl1 wyif.
• Rows 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32: K1, sl1 wyif, *k2, p18, repeat from * to last 4 sts, k2, k1, sl1 wyif.
• Rows 7 and 15: K1, sl1 wyif, *p2, 3/3 LC, k12, repeat from * to last 4 sts, p2, k1, sl1 wyif.
• Rows 23 and 31: K1, sl1 wyif, *p2, k12, 3/3 RC, repeat from * to last 4 sts, p2, k1, sl1 wyif.