From the Schelling model of segregation, we derive models of group formation that shed light on segregation or mixing patterns observed in spatial grid networks. Individuals have types and see type-dependent benefits or drawback from theirs neighbours: this leads each one to be attracted or repulsed by its own like or unlike. This framework allows to studying many spatial phenomena that involve individuals making location choices as a function of the characteristics and choices of their neighbours. Our goal is to grow social structures in silico and to ask if related micro-specifications generate similar macro-phenomena of interest. Regarding (i) the amount of segregation-mixing, (ii) the congruence between micro-motives and macro-behaviour and (iii) the nature of frontier between clusters, we examine the properties of the steady-state equilibrium.