Tangible user interfaces take various forms: their design is often unique. As the number of systems is increasing, as understanding the whole becomes difficult. Yet, open innovation approaches require identifying and being inspired by previous solutions. By taking into account the line of descent of technological systems, we use a classification method from biology in HCI: the cladistic classification. The aim is to develop an original approach to characterize the variety of tangible interfaces. This paper presents our approach to develop a list of criteria and to develop a web application for the purpose of a collaborative inventory.