  We present numerical solution of the chlorine dioxide-iodine-malonic acid
reaction-diffusion system in two dimensions in a boundary-fed system using a
realistic model. The bifurcation diagram for the transition from non-symmetry
breaking structures along boundary feed gradients to transverse symmetry
breaking patterns in a single layer is numerically determined. We find this
transition to be discontinuous. We make connection with earlier results and
discuss prospects for future work.
