Shown with a cast-on count of 15 stitches.  

• Rows 1 and 3 (RS): *P1, k1, p1, wrap 3 sts, repeat from * to last 3 sts, p1, k1, p1.
• Rows 2, 4, and 6: *K1, p1, k1, p3, repeat from * to last 3 sts, k1, p1, k1.
• Row 5: *P1, k1, p1, k3, repeat from * to last 3 sts, p1, k1, p1.
• Rows 7 and 9: *Wrap 3 sts, p1, k1, p1, repeat from * to last 3 sts, wrap 3 sts.
• Rows 8, 10, and 12: *P3, k1, p1, k1, repeat from * to last 3 sts, p3.
• Row 11: *K3, p1, k1, p1, repeat from * to last 3 sts, k3.