Also not sure why you are getting downvoted. We call it "breakthrough", as in piercing though all the layers to connect one simple usecase from front to end. O

Also not sure why you are getting downvoted. We call it "breakthrough", as in piercing though all the layers to connect one simple usecase from front to end. Once we established that that works properly, we think of a way to do it clean and tested for all other usecases. (In the book "the pragmatic programmer" it's called "tracer bullets / code".)