In bridge building, for example, the Romans discovered that if the upstream bridge supports were shaped as a "vee" and pointed into the current, they would survive longer.

例如，在桥梁的建造中，罗马人发现如果逆流的桥梁支撑部分是“V”型的，尖冲着水流，那么支撑部分会存留更长时间。