  The problem of morphogenesis and Turing instability are revisited from the
point of view of dimensionality effects. First the linear analysis of a generic
Turing model is elaborated to the case of multiple stationary states, which may
lead the system to bistability. The difference between two- and
three-dimensional pattern formation with respect to pattern selection and
robustness is discussed. Preliminary results concerning the transition between
quasi-two-dimensional and three-dimensional structures are presented and their
relation to experimental results are addressed.
