  In this paper, we aim at modelling and analyzing the regulation processes in
multi-cellular biological systems, in particular tissues.
  The modelling framework is based on interconnected logical regulatory
networks a la Rene Thomas equipped with information about their spatial
relationships. The semantics of such models is expressed through colored Petri
nets to implement regulation rules, combined with topological collections to
implement the spatial information.
  Some constraints are put on the the representation of spatial information in
order to preserve the possibility of an enumerative and exhaustive state space
exploration.
  This paper presents the modelling framework, its semantics, as well as a
prototype implementation that allowed preliminary experimentation on some
applications.
