Chain 4 and join to form a ring. Round 1 (right side): Chain 3 (counts as dc), 2 dc in ring, (chain 2, 3 dc in ring) 3 times, chain 2. Join with slip stitch to top of beginning chain 3: 4 clusters and 4 corner spaces. Round 2 (wrong side): Chain 3, turn. (2 dc, chain 2, 3 dc) in first corner space, (chain 1, [3 dc, chain 2, 3 dc] in next corner space) 3 times, chain 1. Join with slip stitch to top of beginning chain 3: 8 clusters and 4 corner spaces. Round 3: Chain 3, turn. 2 dc in first chain-1 space, chain 1, (3 dc, chain 2, 3 dc) in next corner space, * chain 1, 3 dc in next chain-1 space, chain 1, (3 dc, chain 2, 3 dc) in next corner space; repeat from * 2 more times, chain 1. Join with slip stitch to top of beginning chain 3: 12 clusters, 8 spaces, and 4 corner spaces. Round 4: Chain 3, turn. 2 dc in first chain-1 space, chain 1, (3 dc, chain 2, 3 dc) in next corner space, * (chain 1, 3 dc in next chain-1 space) twice, chain 1, (3 dc, chain 2, 3 dc) in next corner space; repeat from * 2 more times, chain 1, 3 dc in last chain-1 space, chain 1. Join with slip stitch in top of beginning chain 3: 16 clusters, 12 spaces, and 4 corner spaces. Round 5: Chain 3, turn. 2 dc in first chain-1 space, chain 1, 3 dc in next chain-1 space, chain 1, (3 dc, chain 2, 3 dc) in next corner space, * (chain 1, 3 dc in next chain-1 space) 3 times, chain 1, (3 dc, chain 2, 3 dc) in next corner space; repeat from * 2 more times, chain 1, 3 dc in last chain-1 space, chain 1. Join with slip stitch to top of beginning chain 3: 20 clusters, 16 spaces, and 4 corner spaces. Round 6: Chain 3, turn. 2 dc in first chain-1 space, chain 1, 3 dc in next chain-1 space, chain 1, (3 dc, chain 2, 3 dc) in next corner chain-2 space, * (chain 1, 3 dc in next chain-1 space) 4 times, chain 1, (3 dc, chain 2, 3 dc) in next corner space; repeat from * 2 more times, (chain 1, 3 dc in next chain-1 space) twice, chain 1. Join with slip stitch to top of beginning chain 3: 24 clusters, 20 spaces, 4 corner spaces.