  A concrete model of the free skew-monoidal category Fsk on a single
generating object is obtained. The situation is clubbable in the sense of G.M.
Kelly, so this allows a description of the free skew-monoidal category on any
category. As the objects of Fsk are meaningfully bracketed words in the skew
unit I and the generating object X, it is necessary to examine bracketings and
to find the appropriate kinds of morphisms between them. This leads us to
relationships between triangulations of polygons, the Tamari lattice, left and
right bracketing functions, and the orientals. A consequence of our description
of Fsk is a coherence theorem asserting the existence of a strictly
structure-preserving faithful functor from Fsk to the skew-monoidal category of
finite non-empty ordinals and first-element-and-order-preserving functions.
This in turn provides a complete solution to the word problem for skew monoidal
categories.
