摘要: Three important questions arise when using visual languages: for any given piece of information can we draw a diagram representing that information, reliably interpret the diagrams and reason diagrammatically about information? The desirable answer to all three is yes, but these desires are often conflicting; example, well-formedness conditions be enforced assist interpretation this result in drawability problems. In paper, focus on languages based closed curves, which used numerous computing applications. Many such effectively use spatial properties as containment disjointness. We consider consequences enforcing various conditions, simplicity connectedness minimal regions, relation above questions. suggest refinements order find balance between conflicting desires.