Language-Game, Signal, Rule

In #7 of  Philosophical Investigations, Wittgenstein defines a 'Language-Game' as a process constituted by "language and the actions into which it is woven", his primitive example of which is "one party calls out the words, the other acts on them".  Thus, the fundamental structure of a Language-Game is, as has been proposed here, that of Signal-Response.  However, thereafter, he seems to gloss that interweaving of Language and Action as the "use" of Language,  consequently apparently losing sight of that underlying structure,  e. g. as he begins, at #143, his examination of the Game that is often characterized as 'Following a Rule'.  As a result, he seems to miss the isomorphic relation between 1. fetching an object upon hearing the name of the object, and 2. writing out an infinite numerical series as an application of a mathematical formula--while he does classify the latter as a 'use' of Language, he fails to recognize that the former is as much a rule-governed activity as is the latter.  In other words, any Signal is implicitly a rule, and any Response is Rule-governed behavior, i. e. the section beginning at #143 is not an examination of a specialized Language-Game, but a making explicit what is implicit in all such contexts.