Chain a length to equal desired width in multiples of 2 + 1
Row 1: Sc in 2nd ch from hook, dc in next ch, (sc in next ch, dc, in next ch) across, turn (you will have an even number of stitches).
Row 2: Ch 1, (sc in next st, dc in next st) across, turn. Repeat this row until you have the desired size.
Finishing: Working around outer edge, ch 1, sc in each st and in end of each row around with 3 sc in each corner, join with sl st in first sc. Fasten off.