Well, that makes me think about Excel ! I think what the author describes is why Excel is so heavily used. It's often not easy to clearly define the specificat

Well, that makes me think about Excel ! I think what the author describes is why Excel is so heavily used. It's often not easy to clearly define the specifications - but it's easy to play a bit with the data the user knows, and discover some flaws in the logic, corner cases etc. And also very easy to prototype processes. I almost miss it.