Shown with a cast-on count of 20 stitches.  

• Rows 1 and 21 (RS): *K1, p1, repeat from *.
• Rows 2 and 22: *K1, p1, repeat from *.
• Row 3: *P1, k9, repeat from *.
• Row 4: *P9, k1, repeat from *.
• Row 5: *K1, p1, k7, p1, repeat from *.
• Row 6: *K1, p7, k1, p1, repeat from *.
• Row 7: *P1, k1, p1, k5, p1, k1, repeat from *.
• Row 8: *P1, k1, p5, k1, p1, k1, repeat from *.
• Row 9: *K1, p1, k1, p1, k3, p1, k1, p1, repeat from *.
• Row 10: *K1, p1, k1, p3, k1, p1, k1, p1, repeat from *.
• Row 11: *P1, k1, repeat from *.
• Row 12: *P1, k1, repeat from *.
• Row 13: *K5, p1, k4, repeat from *.
• Row 14: *P4, k1, p5, repeat from *.
• Row 15: *K4, p1, k1, p1, k3, repeat from *.
• Row 16: *P3, k1, p1, k1, p4, repeat from *.
• Row 17: *K3, p1, k1, p1, k1, p1, k2, repeat from *.
• Row 18: *P2, k1, p1, k1, p1, k1, p3, repeat from *.
• Row 19: *K2, [p1, k1] 4 times, repeat from *.
• Row 20: *[P1, k1] 4 times, p2, repeat from *.
• Repeat rows 1-20.