Punning
People often want to use a class to specify the value of some property. An example originating at the University of Karlsruhe[1] is in service modeling. Services are modeled as instances of the a:Service class. For each concrete service (i.e., for each instance of a:Service), the users wanted to state what the input to the service is. Here is an example of a service description:
(1) a:Service rdf:type owl:Class (2) a:Person rdf:type owl:Class (3) s1 rdf:type a:Service (4) s1 a:input a:Person
Note that s1 is an individual due to (1), and that a:Person is a class due to (2); hence, in (4) we have a relationship between an individual and a class. Hence, you need some kind of metamodeling to solve this problem.