They're the result of thousands of years of practice in a painful regenerative process.
它们是数千年在痛苦的再生过程中实践的结果。
英语百科
Regenerative process
In applied probability, a regenerative process is a class of stochastic process with the property that certain portions of the process can be treated as being statistically independent of each other. This property can be used in the derivation of theoretical properties of such processes.