Shown with a cast-on count of 2 stitches.  

• Round 1: K2.
• Round 2: *K1, yo, repeat from * (4 sts).
• Rounds 3-4, 6-9, 11-17, 19-36, and 38-52: Knit.
• Round 5: *K1, yo, repeat from * (8 sts).
• Round 10: *K1, yo, repeat from * (16 sts).
• Round 18: *K3, yo, repeat from * to last st, k1 (21 sts).
• Round 37: *K1, yo, repeat from * (42 sts).