Now, in the next chain space, we're going to make a corner. You need to make 3 trebles, chain 2 and then make another 3 trebles into the same chain space (picture 27)
3 dc in next space; 3 hdc in next space; 3 dc in next space; then another corner - 3 tr, chain 2, 3 tr in next space (picture 28)