FIGURE 4. Log of cumulative frequency of log cluster sizes.
From the following article:
Clusters of ant colonies and robust criticality in a tropical agroecosystem
John Vandermeer, Ivette Perfecto & Stacy M. Philpott
Nature 451, 457-459(24 January 2008)
doi:10.1038/nature06477
a, From field samples, based on a minimum distance of 20 m between nests that are judged to be in the same cluster. b, From field-parameterized cellular automata stochastic model, based on a 90 
120 lattice, where each lattice point is intended to model a single shade tree. Clusters are defined based on individual lattice points in contact with any other lattice point in the Moore neighbourhood.