Shown with a cast-on count of 21 stitches.  

• Row 1 (RS): K21.
• Row 2: P21.
• Row 11: K20, turn (20 sts).
• Row 12: P18, turn (18 sts).
• Row 13: K16, turn (16 sts).
• Row 14: P14, turn (14 sts).
• Row 15: K12, turn (12 sts).
• Row 16: P10, turn (10 sts).
• Row 17: K8, turn (8 sts).
• Row 18: P6, turn (6 sts).
• Row 19: K4, turn (4 sts).
• Row 20: P5, turn (5 sts).
• Row 21: K6, turn (6 sts).
• Row 22: P8, turn (8 sts).
• Row 23: K10, turn (10 sts).
• Row 24: P12, turn (12 sts).
• Row 25: K14, turn (14 sts).
• Row 26: P16, turn (16 sts).
• Row 27: K18, turn (18 sts).
• Row 28: Purl to last 2 sts, p2tog.
• Row 41: K1, incR, k1, incR, knit to last 2 sts, incL, k1, incL, k1 (4 more sts).
• Row 42: Purl.
• Repeat rows 41-42.