'Doubled' in the Bible

The breastpiece shall be square and folded double; a span [about nine inches] in length and a span in width.

It was square; they made the breastpiece folded double, a [hand’s] span long and a [hand’s] span wide when folded double.

“Therefore, son of man, prophesy and strike your hands together; and let the sword be doubled the third time [in intensity], the sword for the slain. It is the sword for the great slaughter which surrounds them [so that no one can escape, even by hiding in their inner rooms],