Base rnd, each side: Multiple of 3 + 2 + corner sts.
Begin 3 sts to left of corner st.
Rnd 1: Ch 5 (counts as dc and ch-2), skip 2 sts, *[dc in next dc, ch 2, skip 2 sts] to corner st, (dc, ch 3, dc, ch 2) in corner st, skip 2 sts; rep from * around; join with slip st to 3rd ch of ch-5.
Rnd 2: Ch 1, *(sc, hdc, dc, hdc, sc) in each ch-space to corner space, (sc, hdc, 2 dc, hdc, sc) in corner space; rep from * around, ending (sc, hdc, dc, hdc, sc) in last space, join with slip st to first sc. Fasten off.