Shown with a cast-on count of 35 stitches.  

• Row 1 (RS): Yo, k2tog, k1, [k2tog, k2, yo, k1, yo, k2, ssk, k1] 3 times, ssk, yo.
• Rows 2, 4, 6, 8, 10, 12, 14, 16, and 18: Purl.
• Row 3: Yo, k2tog, k1, yo, k2, ssk, k1, k2tog, k2, yo, k1, yo, k2, ssk, k1, k2tog, k2, yo, k1, yo, k2, ssk, k1, k2tog, k2, yo, k1, ssk, yo.
• Row 5: Yo, k2tog, yo, k1, [yo, k2, ssk, k1, k2tog, k2, yo, k1] 3 times, yo, ssk, yo (37 sts).
• Row 7: Yo, k2tog, k1, yo, k1, [yo, k2, ssk, k1, k2tog, k2, yo, k1] 3 times, yo, k1, ssk, yo (39 sts).
• Row 9: Yo, k2tog, k2, yo, k1, [yo, k2, ssk, k1, k2tog, k2, yo, k1] 3 times, yo, k2, ssk, yo (41 sts).
• Row 11: Yo, k1, yo, ssk, k1, k1 PB, k1, [k1 PB, k1, k2tog, yo, k1, yo, ssk, k1, k1 PB, k1] 3 times, k1 PB, k1, k2tog, yo, k1, yo (43 sts).
• Row 13: Yo, k1, yo, k1, yo, k1, ssk, k1, k1 PB, [k1, k2tog, k1, yo, k1, yo, k1, ssk, k1, k1 PB] 3 times, k1, k2tog, k1, yo, k1, yo, k1, yo (47 sts).
• Row 15: Yo, k2tog, k1, yo, k1, yo, k2, ssk, k1, [k2tog, k2, yo, k1, yo, k2, ssk, k1] 3 times, k2tog, k2, yo, k1, yo, k1, ssk, yo (49 sts).
• Row 17: Yo, k2tog, k2, yo, k1, yo, k3, sl1-k2tog-psso, [k3, yo, k1, yo, k3, sl1-k2tog-psso] 3 times, k3, yo, k1, yo, k2, ssk, yo (51 sts).