We characterize aperiodic distributed behaviours, modelled as Mazurkiewicz traces in terms of a very natural cascade product of the gossip automaton with a counter-free asynchronous automaton. The characterization strengthens the fundamental results of Schutzenberger and, McNaughton and Papert and implies that star-free, equivalently, first-order-definable trace languages admit counter-free asynchronous acceptors modulo the gossip automaton