  Interviews run on people, programs run on operating systems, voting schemes
run on voters, games run on players. Each of these is an example of the
abstraction pattern runs on matter. Pattern determines the decision tree that
governs how a situation can unfold, while matter responds with decisions at
each juncture.
  In this article, we will give a straightforward and concrete construction of
the free monad monad for $(\mathbf{Poly}, \mathbin{\triangleleft},
\mathcal{y})$, the category of polynomial functors with the substitution
monoidal product. Although the free monad has been well-studied in other
contexts, the construction we give is streamlined and explicitly illustrates
how the free monad represents terminating decision trees. We will also explore
the naturally arising interaction between the free monad and cofree comonad.
Again, while the interaction itself is known, the perspective we take is the
free monad as a module over the cofree comonad. Lastly, we will give four
applications of the module action to interviews, computer programs, voting, and
games. In each example, we will see how the free monad represents pattern, the
cofree comonad represents matter, and the module action represents runs on.
