Well you know what a point is, it's got an x- and a y- coordinate, it's natural to think about those two things as belonging as a single entity.

把这两个坐标认为，是属于一个独立的实体，是理所当然的事情,因此实现这个目的的。

麻省理工公开课 - 计算机科学及编程导论课程节选