The mound collapsed. “I allow you to construct three kinds of raised foundations: raised foundations of brick, stone, and wood.” It was difficult to get up to the gatehouses. “I allow three kinds of stairs: stairs of brick, stone, and wood.” People fell down while climbing the stairs. “I allow rails.” The gatehouses didn’t have doors. “I allow doors, door frames, lower hinges, upper hinges, door jambs, bolt sockets, bolts, latches, keyholes, door-pulling holes, and door-pulling ropes.”