You can kind of see where the syntax is going, looks like a loop, but you can kind of put blocks inside of you, and the little arrow suggests that once you get to the bottom just like our socks example, you're gonna do the following again.

从某种程度上你可以看到它的语法构成,像个循环，你也可以把，一些程序块放到循环中，如同短袜的例子，这个小箭头暗示你一旦到达底部,你将会重复接下来的事情。

哈佛公开课 - 计算机科学课程节选

So I am going to on the fly write a very simple little main program that just illustrates some of the syntax that we can then visualize more interesting.

我很快的写了一个很简单地小程序,来说明一些语法,我们使它变得更有趣些。

哈佛公开课 - 计算机科学课程节选