The paper deals with the specification of dynamic reconfiguration of complex systems. We show how dynamic reconfiguration and especially components mobility, affects the ongoing behaviour of the reconfigured parts and its side effects on the system as a whole. Our approach is based on software architectural viewpoint of hierarchical systems, considered as sets of independent components and links. Nevertheless, the recursive description of components structure and particularly hierarchical and compositional generation of components and system behaviour, needs additional concepts. For this reason, we define a tile logic based model, where interfaces constitute basic objects that undergo the two dimensional dynamics of reconfigurable software systems. Spatial distribution of interfaces defines system / hierarchical component structural configuration. Dynamic reconfiguration is then regarded as a redistribution operation of these interfaces. On the other hand, tuples of interfaces values define system / hierarchical component behavioural configurations. The incremental and compositional definition of both system structure and behaviour is obtained thanks to the horizontal composition operator of tile logic that establishes dynamic connections between components interfaces and at the same time propagates the corresponding action effects on the environment. For further information, please visit this web site.