  Excitable media are prevalent models for describing physical, chemical, and
biological systems which support wave propagation. In this letter, we show that
the time evolution of the medium state at the wave fronts can be determined by
complicated chaotic attractors. Wave front dynamics can be controlled by
initial data choice. Building on this groundwork, we show that there is a
mechano-chemical analog of the Universal Turing machine for morphogenesis
problems. Namely, a fixed mechano-chemical system can produce any prescribed
cell pattern depending on its input (initial data). This universal mechanism
uses fundamental physical effects: spontaneous symmetry breaking with formation
of many interfaces (kinks), which interact non-locally via a fast diffusing
reagent. This interaction creates chaos. We present algorithms allowing us to
obtain a prescribed target cell pattern.
