What disappears when an eight-foot plank is sawn in half, yielding two less-than-four-foot boards, a solid term for what’s lost to the teeth of separation. Neither sawdust nor error, nor the labor of gremlins waiting to wreak havoc on perfectly accurate measurements. Kerf—you will know it by its absence, like divided attention. Small consolation: each board as it’s halved releases both sides of a single scent, limewood for linden, pine for pine.