@prefix owl: <http://www.w3.org/2002/07/owl#>.
@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#>.
@prefix : <foo:bla#>.
:XYThing owl:hasKey (:x :y).
:xy10 a :XYThing; :x 10; :y 10; :text "free".
:XYTen owl:intersectionOf ([ a owl:Restriction; owl:onProperty :x; owl:hasValue 10]
                           [ a owl:Restriction; owl:onProperty :y; owl:hasValue 10]
               [ a owl:Restriction; owl:onProperty :text; owl:hasValue "pointedTo"]).
:pointTo a owl:FunctionalProperty; rdfs:range :XYThing.
:foo a [ a owl:Restriction;
         owl:onProperty :pointTo; owl:onClass :XYTen; owl:qualifiedCardinality 1].
# :foo :pointTo :xyxy.   ## functionality of pointTo: makes :xyxy=(10,10) explicit