From the description: This shawl is a crocheted version of the knitted pi-shawl, made famous by Elizabeth Zimmerman, and uses the same mathematical principle, each time you double the diameter of a circle you double the circumference. The numerical pattern works for any weight of yarn and you can continue crocheting until your shawl is as big as a tablecloth if you like. Large sections of treble crochet between increase rounds gives you plenty of room to add other stitch patterns that are based on trebles, such as filet patterns, bobbles, clusters and shells.

Note: Pattern uses AUS/UK crochet notation.

Yarn: any smooth yarn from laceweight to bulky.

Needles and Notions: choose a crochet hook a couple of sizes larger than the size usually used for your yarn.

Tension: not critical, it’s best if your tension is a little looser than normal for your chosen yarn so the shawl has plenty of drape, and does not pucker with the increase rounds. Expect a small amount of puckering, this will disappear with good blocking on completion.