Shown with a cast-on count of 31 stitches.  

• Rows 1 and 3 (RS): K1, *yo, k3, sl1-k2tog-psso, k3, yo, k1, repeat from *.
• Rows 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20: Purl.
• Row 5: K1, *k1, yo, k2, sl1-k2tog-psso, k2, yo, k2, repeat from *.
• Row 7: K1, *k2, yo, k1, sl1-k2tog-psso, k1, yo, k3, repeat from *.
• Row 9: K1, *k3, yo, sl1-k2tog-psso, yo, k4, repeat from *.
• Rows 11 and 13: K2tog, k3, yo, k1, yo, k3, *sl1-k2tog-psso, k3, yo, k1, yo, k3, repeat from * to last 2 sts, ssk.
• Row 15: K2tog, k2, yo, k3, yo, k2, *sl1-k2tog-psso, k2, yo, k3, yo, k2, repeat from * to last 2 sts, ssk.
• Row 17: K2tog, k1, yo, k5, yo, k1, *sl1-k2tog-psso, k1, yo, k5, yo, k1, repeat from * to last 2 sts, ssk.
• Row 19: K2tog, yo, k7, yo, *sl1-k2tog-psso, yo, k7, yo, repeat from * to last 2 sts, ssk.