Shown with a cast-on count of 23 stitches.  

• Row 1 (RS): K4, k2tog, yo, ssk, k7, k2tog, yo, ssk, k4 (21 sts).
• Rows 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, and 24: P21.
• Row 3: K2tog, k3, yo, k1, yo, k3, sl2-k1-p2sso, k3, yo, k1, yo, k3, ssk.
• Rows 5 and 21: K2tog, k2, yo, k3, yo, k2, sl2-k1-p2sso, k2, yo, k3, yo, k2, ssk.
• Rows 7 and 19: K2, yo, k2, sl2-k1-p2sso, k2, yo, k3, yo, k2, sl2-k1-p2sso, k2, yo, k2.
• Row 9: K3, yo, ssk, k1, k2tog, yo, k5, yo, ssk, k1, k2tog, yo, k3.
• Rows 11 and 13: K21.
• Row 15: Yo, ssk, k7, k2tog, yo, k1, k7, k2tog, yo.
• Row 17: K1, yo, k3, sl2-k1-p2sso, k3, yo, k1, yo, k3, sl2-k1-p2sso, k3, yo, k1.
• Row 23: K1, k2tog, yo, k5, yo, ssk, k1, k2tog, yo, k5, yo, ssk, k1.