Shown with a cast-on count of 21 stitches.  

• Rows 1, 3, and 5 (RS): P1, *k2tog, k2, yo, k1, yo, k2, ssk, p1, repeat from *.
• Rows 2, 4, 6, 8, and 10: K1, *p9, k1, repeat from *.
• Row 7: P1, *k2tog, k1, yo, k3, yo, k1, ssk, p1, repeat from *.
• Row 9: P1, *k2tog, yo, k5, yo, ssk, p1, repeat from *.
• Rows 11, 13, and 15: K1, *yo, k2, ssk, p1, k2tog, k2, yo, k1, repeat from *.
• Rows 12, 14, 16, 18, and 20: *P5, k1, p4, repeat from * to last st, p1.
• Row 17: K1, *k1, yo, k1, ssk, p1, k2tog, k1, yo, k2, repeat from *.
• Row 19: K1, *k2, yo, ssk, p1, k2tog, yo, k3, repeat from *.