Some mathematical sketches are just aesthetic. Here's some of my favourites.
Action of a category on a set (from here)Unrolling in time of a cybernetic process (sketch)The definition of the hom-set functor oof a triple category on a square. Notes from
reading this.A sketch of Harsanyi reduction of Bayesian games, in the graphical language of open
gamesSketches from a discussion with Bruno about the internal model principle.Unpublished coherence diagram for a (T,S)-bialgebra where T and S are 2-monads. This
is the pentagon axiom.Unpublished coherence diagram for a (T,S)-bialgebra where T and S are 2-monads. This
is the triangle axiom.The commuting space invader (from here)The anatomy of a dependent lens.
