This was uttered while making a second attempt at lugging a couch down a set of stairs. It’s a congruent conflation of “back to square one” and “starting from scratch” both meaning a starting place or at the beginning. These phrases seem to be a continual source of confusion. For example, I’ve posted “back to square zero” https://malaphors.com/2017/03/24/were-back-to-square-zero/ and “starting from ground one” https://malaphors.com/2012/11/07/starting-from-ground-one/. Both confuse the many phrases that describe a new beginning or starting over. While a square is certainly not a zero, the mind might be mixing them. One and zero are both numbers, and scratch and square are both similar in sound. A tip of the hat to John Kooser for muttering this one and passing it on!