  This model describes cluster aggregation in a stirred colloidal solution
Interacting clusters compete for growth in this 'winner-takes-all' model; for
finite assemblies, the largest cluster always wins, i.e. there is a uniform
sediment. In mean-field, the model exhibits glassy dynamics, with two
well-separated time scales, corresponding to individual and collective
behaviour; the survival probability of a cluster eventually falls off according
to a universal law $(\ln t)^{-1/2}$. In finite dimensions, the glassiness is
enhanced: the dynamics manifests both {\it ageing} and metastability, where
pattern formation is manifested in each metastable state by a fraction of {\it
immortal} clusters.
