Foundation, color A- Ch4, sl st into 1st ch to join.
Rnd 1 - Ch3 (counts as dc), 2dc, *ch2, 3dc, rpt from * 2 more times, ch1, 1hdc in top of ch-3 to join. [12dc and 4 x ch-2sps]
Rnd 2 - Ch1 (not counted as an st), sc around hdc made in last rnd, * sk-1dc and make (3dc, ch2, 3dc) in next dc, sk next dc and sc in ch-2 sp, rpt from * 2 more times, sk-1dc and make (3dc, ch2, 3dc) in next dc, sk next dc and sl st in top of sc to join. [24dc, 4sc, and 4 x ch-2 sps]
Rnd 3, color B - Ch3 (counts as a dc), 2dc, ch2, 3dc into same space as ch-3, * ch1, sc in ch-2 sp, ch1, (3dc, ch2, 3dc) in next sc, rpt from * 2 more times, ch1, sc in ch-2 sp, ch1, sl st intop of ch-3 to join. [24dc, 4sc, 4 x ch-2 sps, 8 x ch-1 sps]
Rnd 4, color A - Ch1 (not a st), sc in same sp as ch-1, 1sc in next 2-sts, * (1sc, ch2, 1sc) in ch-2 sp, 1sc in next 3-sts, 1sc in ch-1 sp, 1sc in next st, 1sc in ch-1 sp, 1sc in next 3-sts, rpt from * 2 more times, (1sc, ch2, 1sc) in ch2 sp, 1sc in next 3-sts, 1sc in ch-1 sp, 1sc in next st, 1sc in ch-1 sp, sl st in top of sc to join. [44sc, 4 x ch-2 sps]
Rnd 5, color B - Ch3 (counts as dc), 1dc in next 4-sts, * (1dc, ch2, 1dc) in ch-2 sp, 1dc in next 11 sts, rpt from * 2 more times, (1dc, ch2, 1dc) in ch-2 sp, 1dc in next 6-sts, sl st into ch-3 to join, ch1, cut yarn and fasten off. [52dc, 4 x ch-2 sps]
Finish - Use a yarn needle to weave in the loose ends and if necessary block the squares to ensure that they are of an even size and shape to make joining easier.