Shown with a cast-on count of 21 stitches.  

• Row 1 (WS): P21.
• Row 2: Kfb, k19, kfb (23 sts).
• Row 3: P23.
• Row 4: Kfb, k21, kfb (25 sts).
• Row 5: P25.
• Row 6: Kfb, k23, kfb (27 sts).
• Row 7: P27.
• Row 8: Kfb, k25, kfb (29 sts).
• Row 9: P29.
• Row 10: Kfb, k27, kfb (31 sts).
• Row 11: P31.
• Row 12: CO 19 sts, kfb, k29, kfb (52 sts).
• Row 13: P52.
• Row 14: K48, w&t (48 sts).
• Row 15: P48.
• Row 16: K44, w&t (44 sts).
• Row 17: P44.
• Row 18: K40, w&t (40 sts).
• Row 19: P40.
• Row 20: K36, w&t (36 sts).
• Row 21: P36.