BioSystems 76 (2004) 157–167 Artificial cell division Daniel Mange ∗ , André Stauffer, Enrico Petraglio, Gianluca Tempesti Swiss Federal Institute of Technology, Logic Systems Laboratory, CH-1015 Lausanne, Switzerland Received 28 February 2003; received in revised form 11 July 2003; accepted 1 August 2003 Abstract After a survey of the theory and some realizations of self-replicating machines, this paper presents a novel self-replicating loop endowed with universal construction and computation properties. Based on the hardware implementation of the so-called Tom Thumb algorithm, the design of this loop leads to a new kind of cellular automaton made of a processing and a control units. The self-replication of the Swiss flag serves as an artificial cell division example of the loop which, according to autopoietic evaluation criteria, corresponds to a cell showing the phenomenology of a living system. © 2004 Elsevier Ireland Ltd. All rights reserved. Keywords: Self-replication; Universal construction; Universal computation; Cellular automaton; Artificial cell division; Autopoiesis 1. Introduction and survey 1.1. John von Neumann’s self-replicating automaton The main goal of this paper is to present a new self-replicating machine endowed with universal con- struction and computation properties. The early his- tory of the theory of self-replicating machines is ba- sically the history of von Neumann’s (1996) thinking on the matter. von Neumann’s cellular automaton, as well as all the machines described in this paper, is based on the following general hypotheses. • The automaton deals exclusively with the flow of information; the physical material (usually a silicon substrate) and the energy (power supply) are given a priori. • The physical space is two-dimensional and as large as desired. ∗ Corresponding author. E-mail address: daniel.mange@epfl.ch (D. Mange). • The physical space is homogeneous, that is com- prised by identical molecules, 1 all of which have the same internal architecture and the same connections with their neighbors; only the state of a molecule (the combination of the values in its memories) can distinguish it from its neighbors. • Replication is considered as a special case of growth: this process involves the creation of an identical organism by duplicating the genetic mate- rial of a mother entity onto a daughter one, thereby creating an exact clone. In his historical work, von Neumann showed that a possible configuration (a set of molecules in a given state) of his automaton can implement a universal con- structor (Uconst) endowed of the three following prop- erties. 1 To avoid conflicts with biological definitions, we do not use the term “cell” to indicate the parts of a cellular automaton, opting rather for the term “molecule”. In fact, in biological terms, a cell can be defined as the smallest part of a living being which carries the complete blueprint of the being, that is the being’s genome. 0303-2647/$ – see front matter © 2004 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.biosystems.2004.05.010