Concepts appear and disappear. How easy it is to lose track of them in the myriad relationships, of depth to shallowness, of volume to plane, of density to clarity, small to large, palpable life to something dead. The stone remains to be attacked again. It is stone, stone all the way through, always remaining, never really lost or destroyed, excepting as we may lose courage and imagination. Time Thinking must have taken ten years, often worked on, waiting.