This article explores the use of diagramming to support simultaneous sensemaking and ontology development. The authors argue that tools can be developed to support a continuum of knowledge models, from initial free-form diagrams that make it easy to capture anauthorés knowledge and intent but are only interpretable by humans, to propositionally coherent concept maps that structure the free-form diagrams into independently meaningful node-link-node triples, and finally to description-logic concept maps that combine human readability and understanding with logical formalism and a machine-understandable format. The CmapTools Ontology Editor (COE) is a version of CmapTools that uses a descriptive-logic style to encode meanings. Rendering Web Ontology Language (OWL) into concept map notation may be regarded as a first marker in the territory that lies toward the formal end of a continuum of human-machine functionality. In COE-OWL diagrams, the machine reads the parts of the diagram that it can and performs allowable logical operations, while ignoring the parts of the diagram it cannot read. Conversely, humans read those parts of the diagram that make sense and can ignore the rest, knowing that the two formsóthe natural and the logicalóare linked in a way that is itself meaningful and functional. The authors call this merger of ontology creation and sensemaking ìopportunistic computation.