**3. General spirit of operads**

Little n-cubes is a "primordial operad" that clearly illustrates the general spirit and intent of a wide range of applications of operads.

Objects conceived as _interfaces_, and a morphism \\(X_1,...,X_n \rightarrow Y\\) is conceived as an arrangement of the sub-interfaces \\(X_1,...,X_n\\) within the enclosing interface \\(Y\\).

_Composition_ of morphisms is the operation of nesting arrangements and removing the intermediate interfaces.

A tree of connected morphisms can represent a decomposition of a system using a hierarchy of abstractions.

Composition of the morphisms gives the opposite process: _concretization_, to give an arrangement that explicitly includes all of the most granular components in the system.