In construction grammar (2), the realisation of argument roles in terms of core grammatical relations (subject, direct object or indirect object). Other argument roles may optionally be present in the sentence but represented as prepositional phrases, sometimes called 'oblique' objects. For instance, in the example: The thief opened the window with the crowbar, the argument roles agent and patient lexicalized by the thief and the window respectively are constructionally profiled as they are associated with a 'direct' grammatical relation: subject and object. However, the argument role instrument lexicalized by the crowbar is not constructionally profiled as it is not associated with a 'direct' grammatical relational but rather is introduced by a preposition and thus constitutes an 'oblique' object.