I used Yarn Bee, Breathe Deep Yarn, with a size G crochet hook, any 4 medium weight yard should produce the same size. You can make 2 or 3 of these with one skein.

sc = single crochet
hdc = half double crochet
fptrc = front post treble crochet
sl st = slip stitch
dc = double crochet

Gauge – 13 rows, 10 sts = 2 ½” square