If the abstractions evolve over time you still in compliance with the law. But if you try to think-up all the abstractions and their interfaces before you have

If the abstractions evolve over time you still in compliance with the law. But if you try to think-up all the abstractions and their interfaces before you have a working system -- you are likely to find yourself in violation of Gall's Law. Many expensive complex systems have been built this way, very few of them have worked :)