Man uses his right hand more often than his left, and consequently his various instruments and equipment (staircases, locks, watch springs, etc.) are designed to be used in a right–to–left manner.

人类使用右手的频率多于左手，因此他的各种仪器和设备（楼梯、锁、手表弹簧等）被设计为以从右到左的方式使用。