  A model of discrete spacetime on a microscopic level is considered. It is a
directed acyclic dyadic graph. This is the particular case of a causal set. The
goal of this model is to describe particles as some repetitive symmetrical
self-organized structures of the graph without any reference to continuous
spacetime. The dynamics of the model is considered. This dynamics is stochastic
sequential additions of new vertexes. Growth of the graph is a Markovian
process. This dynamics is a consequence of a causality principle.
