Numerical simulation by Pearson revealed a surprising variety of spatiotemporal patterns in a simple two-dimensional reaction-diffusion system. The mutual (or global) interaction between the overall reaction rate in a thin slab and the reactants concentrations in the surrounding vessel may have a strong impact on the dynamics of the system. It may lead to formation of patterns even when diffusion-reaction interactions cannot create patterns. Changes in this global interaction, which can be accomplished by changes in the reactant flow rate, may change the qualitative shape of the pattern and cause it to appear or disappear. Patterns of qualitatively different nature may be obtained for different initial conditions.