  We propose that the behaviour of non-linear media can be controlled
automatically through coevolutionary systems. By extension, forms of
unconventional computing, i.e., massively parallel non-linear computers, can be
realised by such an approach. In this study a light-sensitive sub-excitable
Belousov-Zhabotinsky reaction is controlled using various heterogeneous
cellular automata. A checkerboard image comprising of varying light intensity
cells is projected onto the surface of a catalyst-loaded gel resulting in rich
spatio-temporal chemical wave behaviour. The coevolved cellular automata are
shown to be able to control chemical activity through dynamic control of the
light intensity. The approach is demonstrated through the creation of a number
of simple Boolean logic gates.
