Shown with a cast-on count of 30 stitches.  

• Row 1 (RS): K21, yo, k2tog, k7.
• Rows 2, 8, 10, and 16: K21, purl to last 8 sts, k8.
• Row 3: K18, k2tog, yo, p3, yo, k2tog, k5.
• Rows 4 and 6: K19, p3, k8.
• Row 5: K16, k2tog, yo, p3, yo, k2tog, k7.
• Rows 7, 11, and 15: K18, ssk, yo, p3, yo, ssk, k5.
• Row 9: K20, ssk, yo, k8.
• Rows 12 and 14: K21, p3, k6.
• Row 13: K20, ssk, yo, p3, yo, ssk, k3.