Lovely Square. I changed the border a little as follows:

Rd 10: 1sc ch 2 1sc into corner, 29 sc all along including corner sc.

Rd 11: 1sc, ch 2, 1sc into corner, sk 2sc, ch 3, sc into next st all along (10 x 3 ch spaces)

Rd 12: 2hdc, 2ch, 2hdc into corner, 3 hds into each ch 3 space all along.

Rd 13: 2dc, 2ch, 2dc into corner, 1 dc into each st, (37dcs inc. corner sts on each side).