The purpose of protothreads is to implement sequential flow of control without using complex state machines or full multi-threading. 它的主要作用是執行順序控制流，而無須複雜的狀態機或者多線程。
The downhole stabilizer location adjuster, fixed between the bit and the drill collar, is a special tool for continual deviation control of a slant hole. 井下穩定器安放位置調節器是斜井旋轉鑽井時實施井斜連續控制的專用工具，安裝在鑽頭與鑽鋌之間。
The automatic washing machine is a familiar example of a sequential control system. 自動洗衣機是一個時序控制系統的一個熟悉的例子。
