  Cellular self-assembly and organization are fundamental steps for the
development of biological tissues. In this paper, within the framework of a
cellular automata model, we address how an ordered tissue pattern spontaneously
emerges from a randomly migrating single cell population without the influence
of any external cues. This model is based on the active motility of cells and
their ability to reorganize due to cell-cell cohesivity as observed in
experiments. Our model successfully emulates the formation of nascent clusters
and also predicts the temporal evolution of aggregates that leads to the
compact tissue structures. Moreover, the simulations also capture several
dynamical properties of growing aggregates, such as, the rate of cell
aggregation and non-monotonic growth of the aggregate area which show a good
agreement with the existing experimental observations. We further investigate
the time evolution of the cohesive strength, and the compactness of aggregates,
and also study the ruggedness of the growing structures by evaluating the
fractal dimension to get insights into the complexity of tumorous tissue growth
which were hitherto unexplored.
