Several times she had passed by the front of the same building, or seen it from down the length of a street. For it stood at a place where several ways angled together into a cramped asterisk of wet cobblestones, and so sudden views of it kept jumping into her peripheral vision as she ambled along the nearby alleys. That intersection was there because of a house-sized block of stone that jutted from the hillside and forced all the nearby streets to stretch around it. The stone, as she could guess, was a crumb of the moon’s mantle that had become embedded in its iron core. It might have been in there for a billion years, or it might have been a loose bolide that had slammed into red-hot Peach Pit shortly after Zero and gotten stuck in the congealing metal. Cleft and its siblings had many of those. They were usually treated as impurities in the melt. This one had been left in situ, presenting a rugged gray face to the streets that wrapped around it. Atop it, ten meters above street level, someone had constructed a round stone tower. Fanning out behind, like a ship’s hull behind its jutting prow, was a triangular building that she could guess had a nice compound in its center.