For different initial conditions, the connectivity 〈z〉largest of the largest connected cluster, of the adaptive Boolean network studied by Christensen et al. self-organizes towards the critical value of 2. Adapted from Christensen et al. (1998), fig. 3 (open circle, <z>=2, p=10−2; solid circle, <z>=2, p=10−3; open square, <z>=3, p=10−2; solid square, <z>=3, p=10−3).