CIRCUITRY ANALOGY. “Just as electrical engineers design circuits to perform specific functions, modules have evolved to perform biological functions. The properties of a module’s components and molecular connections between them are analogous to the circuit diagram of an electrical device. As biologists we often try to deduce the circuitry of modules by listing their component parts and determining how changing the input of the module affects its output.”
https://www.nature.com/articles/35011540