Chain a length to equal desired width in multiples of 2 (add 2 for base chain).
Row 1 (right side): 2 dc into 4th ch from hook, *skip 1ch, 2dc into next ch; rep from * to last 2ch, skip 1ch, 1dc into last ch, turn.
Row 2: 3ch (I use 2ch to avoid the hole in the end), *skip 2 sts, 2dc between 2nd skipped st and next st; rep from * to last 2 sts, skip 1 st, 1dc into top of tch (turn chain), turn.
Rep 2nd row. Work until it is a square. Fasten off.
Hint for best results in finishing is to leave ends long and weave the ends through the work using a tapestry needle.