Diagrams, according to Peirce, are icons which represent the relation of the parts of one thing by analogous relations in the sign vehicle. There are structural correspondences between the sign vehicle and its referential object. Since only relations and structures are considered, diagrammatic icons evince a certain degree of arbitrariness. Because of the digital and linear character of language, diagrammatic icons are more frequent in texts than imaginal icons. Diagrammatic iconicity appears in texts when linear relations within the text stand for temporal, spatial, causal, or social relations in the described world. These extralinguistic relations, which structureour experience as complex principles of order, are mirrored in the text as icons. A verbal description of space is necessarily less iconic than a description of time because complex visual expressions have to be transformed by a process of linearization into a temporal succession first. This projection of a temporal structure onto an originally spatial one has the following effect: static objects and configurations in space are now represented in the temporal medium language and are thus transformed from static to dynamic. The asymmetry between objects and configurations in space on the one hand and the temporality of spatial representation on the other is evident.
