Shown with a cast-on count of 36 stitches.  

• Row 1 (RS): *K1, yo, k3, k2tog, k1, ssk, k3, yo, repeat from *.
• Rows 2, 4, 6, 8, 10, 12, 14, 16, 18, and 20: Purl.
• Row 3: *K2, yo, k2, k2tog, k1, ssk, k2, yo, k1, repeat from *.
• Row 5: *K3, yo, k1, k2tog, k1, ssk, k1, yo, k2, repeat from *.
• Row 7: *K4, yo, k2tog, k1, ssk, yo, k3, repeat from *.
• Row 9: *K5, yo, sl2-k1-p2sso, yo, k4, repeat from *.
• Row 11: *K1, k2tog, k3, yo, k1, yo, k3, ssk, repeat from *.
• Row 13: *K1, k2tog, k2, yo, k3, yo, k2, ssk, repeat from *.
• Row 15: *K1, k2tog, k1, yo, k5, yo, k1, ssk, repeat from *.
• Row 17: *K1, k2tog, yo, k7, yo, ssk, repeat from *.
• Row 19: K2tog, yo, k9, *yo, sl2-k1-p2sso, yo, k9, repeat from * to last st, k1.