Triangulations on the plane are frequently used for discretizing geometrical data and relations. Delaunay triangulations are of special importance, since they can be generated easily and the resulting triangles are usually not far from the regular triangles. In discretizing spatial data of protein-ligand complexes we need the three-dimensional analogue of the triangulations. Here we are applying Delaunay decomposition for all the heavy atoms of 3D protein structures. The image is the work of Rafael Ordog.