Shown with a cast-on count of 21 stitches.  

• Row 1 (RS): K21.
• Rows 2 and 8: Sl1 wyif, yo, ssk, yo, ssk, w&t (5 sts).
• Rows 3 and 9: K5.
• Rows 4 and 10: Sl1 wyif, yo, ssk, yo, ssk, k4, w&t (9 sts).
• Rows 5 and 11: K9.
• Row 6: Sl1 wyif, yo, ssk, yo, ssk, k5, k2tog, yo, k1, yo, ssk, w&t (15 sts).
• Row 7: K15.
• Row 12: Sl1 wyif, yo, ssk, yo, ssk, k5, k2tog, yo, k1, yo, ssk, k6 (21 sts).
• Row 13: Sl1 wyib, k20.
• Repeat rows 2-13.