  We show how certain suitably modified N-modular diagrams of integer
partitions provide a nice combinatorial interpretation for the general term of
Zeilberger's KOH identity. This identity is the reformulation of O'Hara's
famous proof of the unimodality of the Gaussian polynomial as a combinatorial
identity. In particular, we determine, using different bijections, two main
natural classes of modular diagrams of partitions with bounded parts and
length, having the KOH terms as their generating functions. One of our results
greatly extends recent theorems of J. Quinn et al., which presented striking
applications to quantum physics.
