层出不穷

Origin and story

The Ministry of Education dictionary offers a possible antecedent in Ye Shi's Southern Song essay Bing Quan Shang (兵權上), in Shui Xin Bie Ji (水心別集), volume 4. Discussing military thought, Ye describes strategies appearing in countless variations with the wording 百出不窮. The word 層出 was also used earlier by Han Yu to describe inventive features of poetry appearing one after another.

The exact modern form is attested in chapter 42 of Twenty Years of Strange Events, in a discussion of recurring examination irregularities. Its derivation is not a securely documented single event. It describes continuing emergence, whether welcome innovations or troublesome problems.