Property:May be constructed with

'May be constructed with' is a relation between a Building Block Variant (BBV) and an Element (EL), that indicates that the Element is an optional part of a Building Block Variant. When a BBV 'may be constructed with' a particular EL, then the infrastructure designer should heed the contents of said Element. Even though the inclusion of that Element in the infrastructure design is not mandatory, the designer is required to look into the contents of the Element.