Shown with a cast-on count of 20 stitches.  

• Rounds 1-9: K1, [p2, k2] 4 times, p2, k1.
• Round 10: P1, k4, yo, k1, yo, k3, p2, k3, yo, k1, yo, k4, p1 (24 sts).
• Rounds 11, 13, 15, 17, 19, 21, 23, 25, and 27: P1, k10, p2, k10, p1.
• Rounds 12 and 20: P1, k6, k3tog, yo, k1, yo, p2, yo, k1, yo, sl1-k2tog-psso, k6, p1.
• Rounds 14 and 22: P1, k4, k3tog, k1, [yo, k1] twice, p2, k1, [yo, k1] twice, sl1-k2tog-psso, k4, p1.
• Rounds 16 and 24: P1, k2, k3tog, k2, yo, k1, yo, k2, p2, k2, yo, k1, yo, k2, sl1-k2tog-psso, k2, p1.
• Rounds 18 and 26: P1, k3tog, k3, yo, k1, yo, k3, p2, k3, yo, k1, yo, k3, sl1-k2tog-psso, p1.
• Round 28: P1, ssk, k6, k2tog, p2, ssk, k6, k2tog, p1 (20 sts).
• Round 29: P1, k8, p2, k8, p1.
• Round 30: P1, ssk, k4, k2tog, p2, ssk, k4, k2tog, p1 (16 sts).
• Round 31: P1, k6, p2, k6, p1.
• Round 32: P1, ssk, k2, k2tog, p2, ssk, k2, k2tog, p1 (12 sts).
• Round 33: P1, k4, p2, k4, p1.
• Round 34: P1, ssk, k2tog, p2, ssk, k2tog, p1 (8 sts).
• Round 35: P1, k2, p2, k2, p1.
• Round 36: P1, ssk, p2, k2tog, p1 (6 sts).
• Round 37: P1, k1, p2, k1, p1.
• Round 38: P1, ssk, k2tog, p1 (4 sts).
• Round 39: P1, k2, p1.
• Round 40: P1, k2tog, p1 (3 sts).
• Round 41: P1, k1, p1.