AbstractThis paper is a small tutorial on tool building with Fujaba. With the help of a small case study, we exemplify how the different requirements of an environment for a visual language may be addressed using Fujaba graph transformations. This covers abstract and concrete syntax, static and operational semantics, and model transformations. This case study shows, how the more sophisticated language elements of Fujaba may be exploited in modeling complex aspects of the desired CASE tool. In addition, we address some not graph grammar related aspects in building such an environment, e.g. the graphical user interface and multi-user support.