Shown with a cast-on count of 9 stitches.  

• Rows 1 and 3 (RS): Knit.
• Rows 2 and 4: Knit.
• Row 5: K2, yo, k2, yo, k1, yo, k2, yo, k2 (13 sts).
• Row 6: K2, p9, k2.
• Row 7: K2, yo, k9, yo, k2 (15 sts).
• Row 8: K2, p11, k2.
• Row 9: K2, yo, k5, k1, k5, yo, k2 (17 sts).
• Row 10: K2, p13, k2.
• Row 11: K2, yo, k13, yo, k2 (19 sts).
• Row 12: K2, p15, k2.
• Row 13: K2, yo, k7, yo, k1, yo, k7, yo, k2 (23 sts).
• Row 14: K2, p19, k2.
• Row 15: K2, yo, k9, k1, k9, yo, k2 (25 sts).
• Row 16: K2, p21, k2.
• Row 17: K2, yo, k10, yo, k1, yo, k10, yo, k2 (29 sts).
• Row 19: K2, p25, k2.
• Row 20: K2, yo, k12, k1, k12, yo, k2 (31 sts).
• Row 21: K2, p27, k2.