Foundation - Ch4, sl st into 1st ch to join.
Rnd 1 - Ch3 (counts as a dc), 2dc into the ring, ch2, *3dc into the ring, ch2, rpt from * 2 more times, sl st into top of ch-3 to join. [12dc, 4x ch-2 sps]
Rnd 2 - Ch2 (counts as dc), 1dc in next 2-sts, (2dc, ch2, 2dc) in ch-2 sp, * 1dc next 3-sts, (2dc, ch2, 2dc) in ch-2 sp, rpt from * 3 more times, sl st into top of ch-2 to join. [28dc, and 4x ch-2 sps]
Rnd 3 - Ch2 (counts as dc), 1dc in next 4-sts, (2dc, ch2, 2dc) in ch-2 sp, * 1dc next 7-sts, (2dc, ch2, 2dc) in ch-2 sp, rpt from * 3 more times, 1dc in next 2-sts, sl st into top of ch-2 to join. [44dc, and 4x ch-2 sps]
Rnd 4 - Ch2 (counts as dc), 1dc in next 7-sts, (2dc, ch2, 2dc) in ch-2 sp, * 1dc next 11-sts, (2dc, ch2, 2dc) in ch-2 sp, rpt from * 3 more times, 1dc in next 4-sts, sl st into top of ch-2 to join. [60dc, and 4 x ch-2 sps]
Adding Extra RoundsYou can expand the size of the solid square pattern by working more rounds.To ensure you maintain the correct stitch count, keep in mind that each additional round will increase by 16 double crochets.The stitch increase occurs within the corner chain-2 spaces in every round. As a result, you will get 2 extra stitches at both the start and end of each side.For example, let us take round 4, which has a total of 60 double crochets, with 15 double crochets on each side.As you progress to round 5, each side will have 19 double crochets.This is made up of the 15 double crochets carried over from round 4, along with an extra 4 double crochet stitches (2 double crochets from each of the corner chain spaces at the beginning and end of the side). Rnd 5 - The stitch count on each side should be 19dc, separated with ch-2 corner sps. [76dc and 4x ch-2 sps]
Rnd 6 - The stitch count on each side should be 23dc, separated with ch-2 corner sps. [92dc and 4x ch-2 sps]
Rnd 7 - The stitch count on each side should be 27dc, separated with ch-2 corner sps. [108dc and 4x ch-2 sps]
When you come to the end of your last round, chain 1, cut the yarn, fasten off, and weave in the ends.