Quote below is from Theory of Constraints Introduction:
I think you can check if the spout has excess capacity if you think about it on its own. Like, if the water is flowing down from there really fast or could flow down there really fast then the size of it is already good enough. I think that may tell you that the constraint is somewhere else.
In a game called Little Big Planet, you could use logic and some tools to create player levels. Sometimes when a level broke, I would isolate some logic to see if it was working well on its own. If it did that told me to look for the “constraint” or mistake elsewhere.