Coordinating a group of robots to work in formation has been suggested for a number of tasks, such as urban search-and-rescue, traffic control, and harvesting solar energy. Algorithms for controlling robot formations have been inspired by biological and organizational systems. In our approach to robot formation control, each robot is treated like a cell in a cellular automaton, where local interactions between robots result in a global organization. The algorithm has been demonstrated in both simulated (Mead & Weinberg 2006) and physical environments (Mead et al. 2007). In this paper, we present a detailed insight into the algorithm and its implementation.