Rickety. The way the children played it, they would build a solid tower out of uniform, wooden blocks. The point was to remove the least important blocks and place them on top, adding to the height of the tower. The game was over when the tower fell, and the collapsor was not under any circumstances allowed to play the game again that day. It must have been a memento mori for their world, with the constant barrage of ice from the sky, filling up the sea. You cannot do this forever; they could have been saying: We don’t intend to.