Shown with a cast-on count of 21 stitches.  

• Row 1 (RS): K21.
• Rows 2, 4, 6, 10, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, and 34: Purl.
• Row 3: K10, ctr dbl inc, k10 (23 sts).
• Row 5: K9, k2tog, yo, k1 tbl, yo, ssk, k9.
• Row 7: K8, k2tog, yo, sl2-k1-p2sso, yo, ssk, k8 (21 sts).
• Rows 8 and 12: P10, ctr dbl inc, p10 (23 sts).
• Row 9: K7, k2tog, yo, k2tog, yo, k1 tbl, yo, ssk, yo, ssk, k7.
• Row 11: K6, k2tog, yo, k2tog, yo, sl2-k1-p2sso, yo, ssk, yo, ssk, k6 (21 sts).
• Row 13: K5, k2tog, yo, k2tog, yo, k2tog, M1L, k1, M1R, ssk, yo, ssk, yo, ssk, k5.
• Row 15: K4, k2tog, yo, k2tog, yo, k2tog, M1L, k3, M1R, ssk, yo, ssk, yo, ssk, k4.
• Row 17: K3, k2tog, yo, k2tog, yo, k2tog, M1L, k5, M1R, ssk, yo, ssk, yo, ssk, k3.
• Row 19: K2, incR, k2tog, yo, k2tog, yo, k2tog, k7, ssk, yo, ssk, yo, ssk, incL, k2.
• Row 21: K3, M1R, ssk, yo, ssk, yo, ssk, k5, k2tog, yo, k2tog, yo, k2tog, M1L, k3.
• Row 23: K4, M1R, ssk, yo, ssk, yo, ssk, k3, k2tog, yo, k2tog, yo, k2tog, M1L, k4.
• Row 25: K5, M1R, ssk, yo, ssk, yo, ssk, k1, k2tog, yo, k2tog, yo, k2tog, M1L, k5.
• Row 27: K6, M1R, ssk, yo, ssk, yo, sl2-k1-p2sso, yo, k2tog, yo, k2tog, M1L, k6.
• Row 29: K7, M1R, ssk, yo, ssk, yo, k1 tbl, yo, k2tog, yo, k2tog, M1L, k7 (25 sts).
• Row 31: K8, M1R, ssk, yo, k5tog, yo, k2tog, M1L, k8 (23 sts).
• Row 33: K9, M1R, ssk, yo, k1 tbl, yo, k2tog, M1L, k9 (25 sts).
• Row 35: K10, k5tog, k10 (21 sts).
• Row 36: Yo, purl (22 sts).