Clearly, if I take a chalk like this one here, and I throw it on the ground, and it breaks in little pieces, if I run the movie backwards that doesn't make sense, right?

很清楚，如果我拿一支这样的粉笔，把它扔到地上，它会摔成碎片，如果我们把这个场景倒过来放映，那是没有意义的，对吧？

youdao

Clearly, if I take a chalk like this one here, and I throw it on the ground, and it breaks in little pieces, if I run the movie backwards that doesn't make sense, right?

很清楚，如果我拿一支这样的粉笔，把它扔到地上，它会摔成碎片，如果我们把这个场景倒过来放映,那是没有意义的，对吧？

麻省理工公开课 - 热力学与动力学课程节选

Here's how it goes: A group of runners (aka pack of hounds) looks for clues (dashes of flour or chalk marks) on the ground to indicate the correct path.

CNN: A drinker's guide to running the world