  Higher-point functions of gauge invariant composite operators in N=4 super
Yang-Mills theory can be computed via triangulation. The elementary tile in
this process is the hexagon introduced for the evaluation of structure
constants. A glueing procedure welding the tiles back together is needed to
return to the original object.
  In this note we present work in progress on n-point functions of BPS
operators. In this case, quantum corrections are entirely carried by the
glueing procedure. The lowest non-elementary process is the glueing of three
adjacent tiles by the exchange of two single magnons.
  This problem has been analysed before. With a view to resolving some
conceptional questions and to generalising to higher processes we are trying to
develop an algorithmic approach using the representation of hypergeometric sums
as integrals over Euler kernels.
