  Diagrams generated by three interpolators in an abstract Kalton-Montgomery
complex like interpolation scheme. We will consider in detail the case of the
first three Schechter interpolators associated to the usual Calder\'on complex
interpolation method in two especially interesting cases: weighted $\ell_2$
spaces, i.e., interpolation pairs $(\ell_2(w^{-1}), \ell_2(w))_\theta$, and
$\ell_p$ spaces, i.e., the interpolation pair $(\ell_\infty, \ell_1)_\theta$,
both at $\theta=1/2$.
