The Super Iterator pattern, like the standard Iterator pattern, traverses an unknown data structure without exposing that structure. With the standard Iterator pattern, clients must create a different iterator for each new structure, and the object returned must be of the specific type stored in the structure, even when they share a common super class. With the Super Iterator pattern, the object returned is of the common super class, and the iterator itself need not be altered when adding a new subtype with custom data structures. The client, however, must change two lines of code to load and instantiate the new subclass.