Everyone probably knows Conway's Law and some smart software architects use it to their advantage. However, there is a 3rd building block that is not mentioned in Conway's Law, but which I see as very relevant for software teams. I have used this 3rd building block in various customer encounters with scaled product and multiple teams and have now cast it into a model: "Conway's Law Extended". There are interactions between these 3 elements in "Conway's Law Extended", which seems un-intuitive and makes it exciting! I explain the model, the effects that prevail, and what you can do to create a positive effect in multi team collaboration and what this does to multi-team decisions.