In §G.10, the theory of multiport scattering was derived, i.e.,
the reflections and transmissions that occur when digital
waveguides having wave impedances
are connected together. It
was noted that when
is a power of two, there are
no multiplies in the scattering relations Eq. (G.89), and that
this fact has been used to build multiply-free reverberators and other
structures using digital waveguide meshes
[406,488,136,368,491,492,369,370,372,50,186,301,300,302,398,31].