Pinaud, BrunoMelançon, GuyDubois, JonathanS. Bruckner, S. Miksch, and H. Pfister2015-02-282015-02-2820121467-8659https://doi.org/10.1111/j.1467-8659.2012.03119.xGraph rewriting systems (GRSs) operate on graphs by substituting local patterns according to a set of rewriting rules. The apparent simplicity of GRSs hides an incredible complexity and turns the study of these systems into an involved task requiring high-level expertise. We designed PORGY, an interactive visual environment to fully support GRSs related tasks, exploiting a long historical tradition of GRSs with node-link representations of graphs. PORGY enables rule-based modeling and simulation steering through graphical representations and direct manipulation of all GRSs components. This paper contributes a design study and task taxonomy relevant to the interactive visualization of GRSs.10.1111/j.1467-8659.2012.03119.x