Crochet pinwheel motif

Beg at center, ch 4, join to form ring.
Rnd 1. 12 sc in ring.
Rnd 2. Sc in 1st sc, ( ch3 sk next sc sc in next sc) 6 times- 6 ch-3 loops.
Rnd 3. Sc in next ch-3 lp. (ch3, sc in next sc, sc in next ch-3 lp) 5 times, ch3 sk next sc, sc in next sc.
Rnd 4. 2 sc in ch-3 lp. (ch3 sk next sc, sc in sc, 2sc in ch-3 lp) 5 times. end ch3 sk next sc, sc in next 2 sc.
Rnd 5. 2 sc in next ch-3 lp.( ch3, sk next sc, sc in each of next 2 sc, 2 sc in next ch-3 lp) 5 times. end ch 3 sk next sc, sc in each next 3sc.
Rnd 6. 2 sc in next ch-3 lp ( ch3, sk next sc, sc in each of the next 3 sc, 2 sc in ch-3 lp) 5 imes, end ch3 sk next sc, sc in each of next 4 sc.
Rnds 7-12. Continue to work in same manner , having 1 more sc before ch-3 lp every round until 11 sc bet ch-3 lps, end last round ch3, sl st in next sc. End off.
This motif was worked into a dress, - 60 motifs in all. The motif gauge -5 inches for small dress & 5.5" for medium. blocked bust size of 34" & 36".
Source: McCall's needlework & crafts Fall/ winter 1962-63.