Looking at the area of interaction, as part of the border, we can see two ideas for its creation.
Is it an area formed by the implicit space where the border lines are shaped to allow for the common space?
Or is is created as being a kind of overlay over de existing border?
Why does this matter? Because it has consequences for the governance, the spirit, the rules of engagement of the interaction. To what extent do the various spheres of influence dominate the interaction?