Do you know Macker by Paul Cantrell? It's a build-time architectural rule checking utility for Java developers. Quite old, but we have been using it for years and it still works great for us.
As I am the code cop here, I tend to torture colleagues with forbidden references ;-) So one made this little modification to a comic from xkcd by Randall Munroe. I came across it recently while organising some project folders... So here it is: