For example, a surveyor might see a road as two edges to be surveyed, the roadwork authority might regard it as an asphalt surface to be maintained, and the driver will see it as a highway.

• 举例来说，测量师可能认为一个路是二个边缘被测绘,公路局可能把它考虑一个用柏油铺成的表面被维护，而且司机将认为它是一个公路。