Shown with a cast-on count of 4 stitches.  

• Row 1 (RS): K1, [ctr dbl inc] twice, k1 (8 sts).
• Rows 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32: Purl.
• Row 3: K1, [k1, ctr dbl inc, k1] twice, k1 (12 sts).
• Row 5: K1, [k1, ctr dbl inc, k3] twice, k1 (16 sts).
• Row 7: K1, [k2tog, ctr dbl inc, k2tog, k2] twice, k1.
• Rows 9, 17, and 25: K1, k3, ctr dbl inc, k2tog, k1, k3, ctr dbl inc, k2tog, k1, k1 (18 sts).
• Rows 11, 19, and 27: K1, k2, k2tog, ctr dbl inc, k2tog, k2tog, k1, k2tog, ctr dbl inc, k2tog, k2tog (16 sts).
• Rows 13, 21, and 29: K1, k1, k2tog, ctr dbl inc, k3, k1, k2tog, ctr dbl inc, k3, k1 (18 sts).
• Rows 15, 23, and 31: K2tog, k2tog, ctr dbl inc, k2tog, k1, k2tog, k2tog, ctr dbl inc, k2tog, k2, k1 (16 sts).