Shown with a cast-on count of 21 stitches.  

• Row 1 (RS): P1, *k2, yo, k1, sl1-k2tog-psso, k3, yo, p1, repeat from *.
• Rows 2, 4, 6, and 8: *K1, p9, repeat from * to last st, k1.
• Row 3: P1, *k3, yo, sl1-k2tog-psso, k2, yo, k1, p1, repeat from *.
• Row 5: P1, *yo, k3, sl1-k2tog-psso, k1, yo, k2, p1, repeat from *.
• Row 7: P1, *k1, yo, k2, sl1-k2tog-psso, yo, k3, p1, repeat from *.