Coherent structures and Liesegang pattern formation

Liesegang rings form in strikingly simple experimental setups. The resulting
patterns, sometimes regular, sometimes irregular, are ubiquitous in nature --- yet
mathematically poorly understood. We present models and results that lead to a conceptual
understanding of existence and creation of such patterns, based on existence, stability, and
bifurcation results for coherent structures in our models. A crucial role is played by pushed
and pulled fronts in spinodal decomposition scenarios.