Cyclic Cellular Automata (CCAs) have been found to provide a natural, beguilingly simple, and elegant infrastructure for the design of sensor systems with sleep-wake scheduling to maximize system lifetime. The Greenberg-Hastings model (GHMZ) [3, 2] defined on the integer lattice Z2 is particularly appropriate and is described as follows. Each grid square of the integer lattice is a cell with a set of k > 1 states and a neighborhood N; the neighborhoods of interest here are the von Neumann neighborhood and the Moore neighborhood. The von Neumann neighborhood Nx of cell x consists of just those cells to thenorth, east, south, and west of x, whereas the Moore neighborhood expands to that 3 ? 3 array of cells with x at its center, i.e., all cells that touch x at a side or vertex. All cells change state synchronously step by step according to aclock cycle and transition function common to all. The local rule for state changes is little more than a counter: The state ?t+1(x) of cell x at time t + 1 is a simple mod k increment: ?t+1(x) = ?t(x) + 1 if ?t(x) > 0. But if ?t(x) = 0;the state is incremented to 1 if and only if it has at least one neighbor in Nx which is currently in state 1.