Shown with a cast-on count of 50 stitches.  

• Row 1 (RS): [K2, p2] 12 times, p2.
• Row 2: [P2, k2] 12 times, p2.
• Row 35: [K2, p2tog] 12 times, k2 (38 sts).
• Row 36: [P2, k1] 12 times, p2.
• Row 37: K2, [p1, k2tog] 11 times, p1, k2 (27 sts).
• Row 38: P2, [k1, p1] 11 times, k1, p2.
• Row 39: K2, [k2tog] 11 times, k3 (16 sts).
• Row 40: P16.
• Row 41: BO 15 sts (1 st).