So pictorially, it's as though there's now some other part of the blackboard here, maybe way up here where I can put anything I want that's accessible to main, that's accessible to swap, that's accessible to increment or any other function I might implement because it is, in fact, global.

绘画般地，它是在这里黑板上的其他部分,可能在这里的上面,我在哪里可以放置这些东西,使它们可以被main函数使用，可以被swap函数使用，可以被increment函数使用,或者我所实现的其它函数,因为它实际上是一个全局变量。

哈佛公开课 - 计算机科学课程节选