I followed the pattern closely, but I did a lot more rows to make my pillow square (I used an 18” by 18” pillow form).

Here is the pattern I used:
Long tail cast on 160 stitches.
Rounds 1-7: (Knit 2, purl 2, knit 8, purl 2, knit 2) 10 times
Round 8: (Knit 2, purl 2, slip 4 stitches purlwise onto cable needle and hold in front, knit 4, knit 4 from cable needle, purl 2, knit 2) 10 times
Rounds 9-96: Repeat 8 round pattern 11 more times (for a total of 12 cable twists).
Rounds 97- 103: Repeat rounds 1-7 one last time.
Bind off using kitchener stitch.
Insert pillow and seam cast on edge shut.