In this paper, a system is proposed that is based on graphic units and generic representations. It has tools for making graphic units and also provides a way to define and maintain changes in the relations between graphic units. This is implemented on the basis of a graph representation where the nodes represent graphic units and the edges relations between graphic units. Changes in the graphic units are propagated through the graph. The paper shows how the theoretical work on graphic units and generic representations leads to the current implementation. The system structure is explained and the way changes in graphic units are propagated through the graph representation.