Because in "Pay it Forward", they capture this very idea of human networks as exponential functions.

电影“让爱传出去，深刻地描述了,人类网络是指数函数的观点。

哈佛公开课 - 幸福课课程节选

You turn on your radio, the radio waves passing by, boom, properly tuned, you detected it.

你打开收音机，无线电波传出来，好好地调试一下，你就检测到它了。

耶鲁公开课 - 死亡课程节选