Shown with a cast-on count of 11 stitches.  

• Row 1 (RS): K2, [yo, k1, yo, k1] 4 times, k1 (19 sts).
• Rows 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, and 40: Purl.
• Row 3: K2, [yo, k3, yo, k1] 4 times, k1 (27 sts).
• Row 5: K2, [yo, k5, yo, k1] 4 times, k1 (35 sts).
• Row 7: K2, [yo, k7, yo, k1] 4 times, k1 (43 sts).
• Row 9: K2, [yo, k9, yo, k1] 4 times, k1 (51 sts).
• Row 11: K2, [yo, k11, yo, k1] 4 times, k1 (59 sts).
• Row 13: K2, [yo, k13, yo, k1] 4 times, k1 (67 sts).
• Row 15: K2, [yo, k15, yo, k1] 4 times, k1 (75 sts).
• Row 17: K2, [yo, k17, yo, k1] 4 times, k1 (83 sts).
• Row 19: K2, [yo, k19, yo, k1] 4 times, k1 (91 sts).
• Row 21: K2, [yo, k21, yo, k1] 4 times, k1 (99 sts).
• Row 23: K2, [yo, k23, yo, k1] 4 times, k1 (107 sts).
• Row 25: K2, [yo, k25, yo, k1] 4 times, k1 (115 sts).
• Row 27: K2, [yo, k27, yo, k1] 4 times, k1 (123 sts).
• Row 29: K2, [yo, k29, yo, k1] 4 times, k1 (131 sts).
• Row 31: K2, [yo, k31, yo, k1] 4 times, k1 (139 sts).
• Row 33: K2, [yo, k33, yo, k1] 4 times, k1 (147 sts).
• Row 35: K2, [yo, k35, yo, k1] 4 times, k1 (155 sts).
• Row 37: K2, [yo, k37, yo, k1] 4 times, k1 (163 sts).
• Row 39: K2, [yo, k39, yo, k1] 4 times, k1 (171 sts).