structure{ region{} } - boundary conditions

contact{}

Example:

contact{                        # (optional)
        name = "source"         # This region will be defined as a contact. In this case the contact is called "source".
}

contact{                        # (optional)
        name = "source"         #
        remove{}                # (optional) If a region overlaps with a previous region that has the contact attribute,
                                # the user might want to remove this contact attribute.
}