In previous work we presented a diagrammatic syntax for logic programming which clearly ‘resembles’ the semantics of predicates as relations, i.e. sets of tuples in the Universe of Discourse. This paper shows diagrams as an alternative formal notation for pure logic programming which not only emphasizes some structural features of logical statements, but could also be useful to conduct visual inferences and to communicate them. This paper describes the current state of our research on a visual inference system for answering visually posed queries by means of diagram transformations. Although the transformations are shown by example we point to their correctness and formal character. We explore two interesting features provided by its diagrammatic nature: First, the ability of intuitively keeping track—within a diagram—of the proof that is built while solving a query, and second, the possibility to represent within a unique diagram the several different alternatives to answer a query.