Shown with a cast-on count of 5 stitches.  

• Rows 1 and 3 (WS): K2, p1, k2.
• Row 2: P2, k1, p2.
• Row 4: P1, k1, yo, k1, yo, k1, p1 (7 sts).
• Rows 5, 7, and 9: K1, purl to last st, k1.
• Row 6: P1, k1, yo, k3, yo, k1, p1 (9 sts).
• Row 8: P1, k1, yo, k2tog, yo, k1, yo, ssk, yo, k1, p1 (11 sts).
• Row 10: P1, k1, yo, k2tog, yo, k3, yo, ssk, yo, k1, p1 (13 sts).
• Rows 11 and 13: K3, purl to last 3 sts, k3.
• Row 12: P3, k1, yo, k2tog, yo, k1, yo, ssk, yo, k1, p3 (15 sts).
• Row 14: P3, k1, yo, k2tog, yo, k3, yo, ssk, yo, k1, p3 (17 sts).
• Row 15: K5, purl to last 5 sts, k5.
• Row 16: P3, p2tog, k1, yo, k2tog, yo, k1, yo, ssk, yo, k1, ssp, p3.
• Row 17: K6, purl to last 6 sts, k6.
• Row 18: P4, p2tog, k1, yo, k3, yo, k1, ssp, purl.
• Row 19: K7, purl to last 7 sts, k7.
• Row 20: P7, yo, sl2-k1-p2sso, yo, purl.