Shown with a cast-on count of 34 stitches.  

• Row 1 (RS): K2, *[k1, yo] twice, k1, sl1-k2tog-psso, k9, repeat from * to last 2 sts, k2.
• Rows 2, 4, 6, 8, 10, 12, 14, 16, and 18: K2, *p15, repeat from * to last 2 sts, k2.
• Row 3: K2, *[k1, yo] twice, k2, sl1-k2tog-psso, k8, repeat from * to last 2 sts, k2.
• Row 5: K2, *[k1, yo] twice, k3, sl1-k2tog-psso, k7, repeat from * to last 2 sts, k2.
• Row 7: K2, *[k1, yo] twice, k4, sl1-k2tog-psso, k6, repeat from * to last 2 sts, k2.
• Row 9: K2, *[k1, yo] twice, k5, sl1-k2tog-psso, k5, repeat from * to last 2 sts, k2.
• Row 11: K2, *[k1, yo] twice, k6, sl1-k2tog-psso, k4, repeat from * to last 2 sts, k2.
• Row 13: K2, *[k1, yo] twice, k7, sl1-k2tog-psso, k3, repeat from * to last 2 sts, k2.
• Row 15: K2, *[k1, yo] twice, k8, sl1-k2tog-psso, k2, repeat from * to last 2 sts, k2.
• Row 17: K2, *[k1, yo] twice, k9, sl1-k2tog-psso, k1, repeat from * to last 2 sts, k2.