楼梯上行下行各在一侧

提示词

概念公共楼梯上少量上行与下行者各占一侧，脚步落在对应踏面，平台有人转向但不站满，人物不跨越挑空。

Place a few ascending and descending people on opposite sides of the public stair, with feet on corresponding treads and occasional turns at the landing, without filling it or crossing the void.