The ontology is composed of three parts: The first part of the ontology describes the VCM icons, and contains 240 classes, 21 relations and 2597 axioms. It includes concepts for the pictograms, shapes and colors used in the VCM language, and graphical con- straints for assembling them into icons. In particular, graphical constraints prevent icons with too many components (e.g. an icon with two central pictograms) or overlapping shape modifiers (e.g. the ‘‘tumor’’ and ‘‘virus’’ shape modifier are overlapping). Fig. 3 shows the top of the first part of the ontology.