Walls require spalls as well as large stones. Our thanks go to Brendan McSherry for this week's proverb. In is simplest sense it is a lesson in masonry. A spall or gallet is a small flake or chip of stone produced by splitting a larger stone.
Practiced masons can create any size and shape chip they want.
A deft blow of the hammer will create a chip to fit any whole in a wall. In fact, the word spall comes from the Old German word spell which means to split. Therefore, walls, especially walls made without mortar, need many of these chips if they are to stand for any length of time. On a deeper level, it is a metaphor about society and about life. Such a situation is comically doomed to failure.