An important facet of the ranking in Rule 4b is that identically-ranked nodes can come from different branches of a ligand. So, for example, in Figure we have a case (VS242), which has four "highest-ranked nodes" that must be sorted by R and S as a group. The result that the two ligands cannot be distinguished in Rule 4b. Note that all of the "rules for sorting" discussed in other works, such as, "The first step of this procedure is the critical choice of the first descriptor for each ligand," are unnecessary in terms of code implementation. These "critical choices," such as determining the descriptor associated with highest-ranking node or the descriptor that occurs the most in the set of highest-ranking nodes or sequentially evaluating both and S as references, simply fall out of the mathematics of the numerical rankings described above. Thus, no such critical choices need to be implemented, though if they are, they might speed the processing.