This square confounded me the first time I attempted to make it, and despite the passage of two years, nothing has really changed except the way I made the square.
Last time, I ended up doing more re-engineering than reverse engineering. Today, I was more faithful to the original, which resulted in these directions:
Chain 4, join with slip stitch to form ring.
Rnd 1: ch 4 (counts as first dc and chain-1), * dc, ch 1 into center of ring. Repeat from * 10 times more. Join to first dc made (12dc and 12 ch-1 spaces) and fasten off.
Rnd 2: Join new color with sl st in any chain-1 space. Ch 3 (counts as first dc), and make 1 dc in same chain-1 space. 2dc in each remaining chain-1 space, join with sl st to first dc (24 dc). Fasten off.
Rnd 3. Using a new color, join with a slip stich in the back ridge of any stitch (the back ridge is the stitch just below the back loop on what is, in this instance, the wrong side of the motif), 2hdc in the back ridge of next stitch, *1 hdc in the back ridge of next stitch, 2hdc in the back ridge of next stitch, repeat from * 10 times more. (36hdc). Fasten off.
Round 4: Using a new color, 1 hdc in each hdc around (36 hdc) fasten off.
Round 5: Using a new color, join with a sl st in any stitch, and chain 3 (counts as first dc)1 dc in same stitch, ch3, 2 dc in same stitch (first corner made), 1 dc in next st, 1 hdc in next st, 1 sc in each of next 4 sts, 1 hdc in next st, 1 dc in next stitch, * 2 dc, ch 3, 2 dc in next stitch, 1 dc in next st, 1 hdc in next st, 1 sc in each of next 4 sts, 1 hdc in next st, 1 dc in next stitch; repeat from * two times more. Join with sl st to first dc made. Finish off.
Here is what the square looked like after I completed the first five rounds:
and here is how it looked in relation to the two-square panel to which it would be joined when the sixth round was worked:
Finally, I got to work on the sixth round, the directions for which are as follows (does not include directions for the joining):
Round 6: With a new color, join with sl st in any ch-3 loop and chain 3 (counts as first dc) work 2dc, ch3, 3dc in to same loop (corner made), [skip 2 sts, 3dc in next st,* sk 1 st, 3dc in next st, repeat from * three times more, (3dc, ch3, 3dc) in next ch-3 loop] repeat from [ to ] 2 times more, skip 2 sts, 3dc in next st,* sk 1 st, 3dc in next st, repeat from * three times more. Join with sl st to first dc made.
Here is how it looked with the new square added to the other two:
I like the challenge of the join-as-you-go because I have to figure out in what order the squares were completed (and joined) and this gives the project the air of working on a puzzle, which only adds to my joy.