Shown with a cast-on count of 25 stitches.  

• Row 1 (RS): Kfb, kfb, kfb, k3, kfb, kfb, k9, kfb, kfb, k3, kfb, kfb, kfb (35 sts).
• Rows 2 and 4: Purl.
• Row 3: Kfb, k2, kfb, kfb, k5, kfb, kfb, k11, kfb, kfb, k5, kfb, kfb, k2, kfb (45 sts).
• Row 5: Kfb, k4, kfb, kfb, k7, kfb, kfb, k13, kfb, kfb, k7, kfb, kfb, k4, kfb (55 sts).