Shown with a cast-on count of 31 stitches.  

• Row 1 (RS): K1, *yo, k2, ssk, p1, k2tog, k2, yo, k1, repeat from *.
• Rows 2, 4, 6, 8, and 20: *P5, k1, p4, repeat from * to last st, p1.
• Row 3: K1, *k1, yo, k1, ssk, p1, k2tog, k1, yo, k2, repeat from *.
• Row 5: K1, *k2, yo, k0, ssk, p1, k2tog, k0, yo, k3, repeat from *.
• Row 7: K1, k2tog, yo, k2, *p1, k2, yo, ssk, k1, k2tog, yo, k2, repeat from * to last 6 sts, p1, k2, yo, ssk, k1.
• Row 9: K2tog, yo, k3, *p1, k3, yo, sl1-k2tog-psso, yo, k3, repeat from * to last 6 sts, p1, k3, yo, ssk.
• Rows 10, 12, 14, 16, and 18: *K1, p9, repeat from * to last st, k1.
• Row 11: *P1, k2tog, k2, yo, k1, yo, k2, ssk, repeat from * to last st, p1.
• Row 13: *P1, k2tog, k1, yo, k3, yo, k1, ssk, repeat from * to last st, p1.
• Row 15: *P1, k2tog, k0, yo, k5, yo, k0, ssk, repeat from * to last st, p1.
• Row 17: *P1, k2, yo, ssk, k1, k2tog, yo, k2, repeat from * to last st, p1.
• Row 19: *P1, k3, yo, sl1-k2tog-psso, yo, k3, repeat from * to last st, p1.
• Repeat rows 1-20.