Within a system, multiple patterns of rule combination may interact in complex ways. I present a detailed analysis of Swahili verb inflection in which simple rules, composite rules and aggregated rules all enter into intricate competition, yielding an extravaganza of deviations from canonical morphotactic criteria. At the center of this discussion are three characteristics of Swahili conjugation: (i) the polyfunctionality of verbal concords (in virtue of which the same rule is used to express the noun class of a verb’s subject, that of its pronominal object, or that of a relativized argument), (ii) the expression of negation (by means of three complementary rules), and (iii) the marking of relative verb forms (whose relativized-argument affix participates in an extensive pattern of affix counterposition). The rule-combining approach to morphotactics allows the interacting details of these subsystems to be resolved into two very general types exhibiting an unexpected degree of economy.