Biochemical reactions in organisms form large and complex networks. Examples are given by the Biochemical Pathways atlas [17] and the well known Boehringer Biochemical Pathways poster [16], see Figure 1. Biochemists are familiar with visual representations of reactions and reaction networks. Automatic visualizations help in understanding the complex relations between the components of the networks and in extracting information from the data. They are very useful for building sophisticated research tools.