在古罗马时代,意大利庞贝市的一些街道上,人、马、车混行,交通经常堵塞,事故时常发生。为了解决这个问题,人们把人行道加高,使人与马、车分离。后来,又在接近马路口的地方,横砌起一块块凸出路面的石头,叫做跳石,作为指示人通过的标志。行人可以踩着跳石穿过马路,而跳石刚好在马 In ancient Rome, some streets in Pompeii, Italy, people, horses, cars mixed, traffic is often blocked, accidents occur frequently. In order to solve this problem, people increase the sidewalks and separate people from horses and cars. Later, again near the intersection, a piece of stone protruding from the ground hung on the road, called the stone jumping, as a sign to indicate the passage of people. Pedestrians can stepping on the stones to cross the road, while the stone jumps right at the horse