The video describes the formation of Turing-like patterns in a reaction-diffusion system where one species, which does not diffuse, is inhomogeneously distributed. It has been speculated that these instabilities are responsible for biological pattern formation, such as leopard spots. A chemical "spot", "stripe" or other inhomogeneous state with a characteristic wavelength evolves from the destabilization of a homogeneous state with no spatial structure.
Turing instabilities are driven by differences in the diffusion coefficients of chemical species. It is now believed that these difference are achieved by selective complexing with immobilized species. This is what is modeled in the simulations. The immobilized complexing agent is distributed in different geometries, ranging from strips with different widths and separations, to regular arrays of disks, to random arrays of disks.
The lengths and widths of the inhomogeneously distributed complexing agent are played against the intrinsic Turing wavelength to obtain the "zoo" of patterns in the video. In the absence of complexing agent the chemical system oscillates and these are the chemical waves one sees in the "holes" between the regions with complexing agents.
J. Voroney, A. Lawniczak and R. Kapral, "Turing Pattern Formation in Heterogeneous Media", Physica D, 99, 303 (1996).
Same configuration; long time dynamics (134KB mpeg-1 movie).
Same configuration; even longer time dynamics (125KB mpeg-1 movie).