Shown with a cast-on count of 27 stitches.  

• Row 1 (RS): K2tog, k2, yo, k1, yo, *k2, ssk, k2tog, k2, yo, k1, yo, repeat from * to last 4 sts, k2, ssk.
• Rows 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20: Purl.
• Row 3: K2tog, [k1, yo] twice, *k2, ssk, k2tog, k2, yo, k1, yo, repeat from * to last 5 sts, k2, ssk, k1.
• Row 5: K2tog, yo, k1, yo, *k2, ssk, k2tog, k2, yo, k1, yo, repeat from * to last 6 sts, k2, ssk, k2.
• Row 7: K2, yo, *k2, ssk, k2tog, k2, yo, k1, yo, repeat from * to last 7 sts, k2, ssk, k3.
• Row 9: K1, yo, *k2, ssk, k2tog, k2, yo, k1, yo, repeat from * to last 8 sts, k2, ssk, k4.
• Row 11: K1, k2tog, *k2, yo, k1, yo, k2, ssk, k2tog, repeat from * to last 6 sts, k2, [yo, k1] twice, ssk.
• Row 13: K2, k2tog, *k2, yo, k1, yo, k2, ssk, k2tog, repeat from * to last 5 sts, k2, yo, k1, yo, ssk.
• Row 15: K3, k2tog, *k2, yo, k1, yo, k2, ssk, k2tog, repeat from * to last 4 sts, k2, yo, k2.
• Row 17: K4, k2tog, *k2, yo, k1, yo, k2, ssk, k2tog, repeat from * to last 3 sts, k2, yo, k1.
• Row 19: K1, yo, k2, ssk, k2tog, *k2, yo, k1, yo, k2, ssk, k2tog, repeat from * to last 2 sts, k2, yo.