Using color A, chain 4, join with sl st into a ring.
Round 1 (RS): ch 3, [sc 1, ch 2] twice, with color B sl st to first of 3 ch. 3 sts and 3 ch sp. Cont with B.
Round 2: [ch 4, 3-st trc cluster in ch sp, ch 4, sc 1 in top of cluster, ch 4, ss in next sc of 1st round] 3 times, ending sl st in sl st of 1st round.
Stitch explanation: 3-st trc cluster — join 3 trc into a cluster: * yrh twice, insert hook in ch-sp, yrh, pull loop through, [yrh, pull yarn through 2 loops] twice; rep from * twice, yrh and pull yarn through all 4 loops on hook.
ABBREVIATIONS / REFERENCES
ch-space = space previously made
sc = single crochet
ch(s) = chain(s)
st(s) = stitch(es)
sl st = slip stitch
trc = treble (triple) crochet
yrh = yarn round hook