Shown with a cast-on count of 3 stitches.  

• Row 1 (WS): P3.
• Row 2: K1, (k1, yo, k1) in next st, k1 (5 sts).
• Rows 3, 7, 11, and 15: Purl.
• Rows 4 and 6: K1, yo, k1, (k1, yo, k1) in next st, k1, yo, k1 (9 sts).
• Row 5: P2tog, k2tog, k1, k2tog, p2tog (5 sts).
• Rows 8 and 10: K1, yo, k3, (k1, yo, k1) in next st, k3, yo, k1 (13 sts).
• Row 9: P2tog, k2, k2tog, k1, k2tog, knit to last 2 sts, p2tog (9 sts).
• Rows 12 and 14: K1, yo, k5, (k1, yo, k1) in next st, k5, yo, k1 (17 sts).
• Row 13: P2tog, k4, k2tog, k1, k2tog, knit to last 2 sts, p2tog (13 sts).
• Row 16: K1, yo, k7, (k1, yo, k1) in next st, k7, yo, k1 (21 sts).
• Row 17: P2tog, k6, k2tog, k1, k2tog, knit to last 2 sts, p2tog (17 sts).