It has since progressed, as it began, by necessarily coupling the topological structural elements of 𝜌 to pre-existing chemical concepts. This coupling process can be premeditated, with researchers actively looking for the traces of some as yet "undiscovered" chemical concept in 𝜌 (e.g. aromaticity), or it can be serendipitous. It occurs explicitly when objects are given names, like "bond paths," and implicitly though the context in which they are used in research.