We remove a pebble, system expands.

移开一粒小石子，系统膨胀一点。

麻省理工公开课 - 热力学与动力学课程节选

There is something that one might be able to hold on to: the knob of something, the little flame of something that ; The grain of sand. -The grain of sand; but there is really not a decent metaphor for it, I think.

一个你可以依靠的支点：,一个不同寻常的想法，一个思想的小火花,就像一粒沙中看世界，-一粒沙中看世界;,不过我认为任何比喻都不够贴切。

普林斯顿公开课 - 人性课程节选