For example, we can start with a single index cell, so that the active index initially starts with (ic₀,s₀,oL₀), where s₀ is the initial state of ic₀, and the output list oL₀ is empty. Let f({},s₀) be 1, so that ic₀ will accept an empty set as input. Let f(V,s₀) be 0 for any non-empty V. If we intend to activate index cells in Ic and post a message y to them, it can be done by an appropriate g function. After that, ic₀ enters a state s_sleep, where no input will be accepted. The t_max can be set to infinity. In other words, the sole purpose of ic₀ is to activate some index cells and post a message to them. By adding states to ic₀appropriately, we can also make ic₀ post individual messages to each of the activated index cells.