First, read the intro to Logic.
Now, we open into the 3D multiverse of Metalogic:
A color is a logic, and
a bead is a system of inference.
A flow of an inner bead to an outer bead is a transformation of one system of inference into another - “thinking of thinking”.
Logics form a metalogic, i.e. a “bifibrant triple category without interchange”.
The key to defining metalogic is the analogy of logics and categories.
A category is a matrix of homs with composition and identity; A logic is a matrix of categories with composition and identity.
In Logic, the language of matrices-with-comp+id is the **co/end calculus.**