This smell is a subtle form of duplication. It exists when you have numerous pieces of code that do the same thing using different kinds or quantities of data or objects.
For example, say you have numerous methods on a class for performing queries. Each of these methods performs a query using specific conditions and data. The more specialized queries you need to support, the more query methods you must create. Pretty soon you have an explosion of methods to handle the many ways of performing queries. You also have an implicit query language. You can remove all of these methods and the combinatorial explosion smell by applying Replace Implicit Language with Interpreter (269).
