In the wet lab, when you varied the force with which you blew through the straw or tapped on the table, you changed the stimulus strength by

Even if we cannot limit the classes involved in the operations of some class, say A, to just one, designing A, so its operations involve few other classes usually leads to a better design than if many classes were involved.

A software engineer can state properties of their model in Alloy or TLA+ and have Alloy or TLA+ exhaustively search for counter-examples up to a given size of model.