Shown with a cast-on count of 8 stitches.  

• Rows 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21 (WS): Purl.
• Row 2: [K1, yo, k1] 4 times (12 sts).
• Row 4: [K1, yo, k1, yo, k1] 4 times (20 sts).
• Row 6: [K1, yo, k1, yo, k1, yo, k1, yo, k1] 4 times (36 sts).
• Row 8: [K1, yo, k1, k2tog, yo, k1, yo, ssk, k1, yo, k1] 4 times (44 sts).
• Row 10: [K1, yo, ssk, k2tog, yo, k1, yo, ssk, k2tog, yo, k1] 4 times.
• Row 12: [K1, yo, k1, yo, ssk, k1, yo, k1, yo, k1, k2tog, yo, k1, yo, k1] 4 times (60 sts).
• Row 14: [K1, yo, k2, yo, ssk, k2tog, yo, k1, yo, ssk, k2tog, yo, k2, yo, k1] 4 times (68 sts).
• Row 16: [K1, yo, k1, yo, k1, ssk, k2tog, k1, yo, k1, yo, k1, ssk, k2tog, k1, yo, k1, yo, k1] 4 times (76 sts).
• Row 18: [K1, yo, k2, ssk, k2tog, k1, yo, k1, yo, k1, yo, k1, yo, k1, ssk, k2tog, k2, yo, k1] 4 times (84 sts).
• Row 20: [K1, yo, k2, ssk, k2tog, k3, yo, k1, yo, k3, ssk, k2tog, k2, yo, k1] 4 times.