  In quantum logical terms, Hardy-type arguments can be uniformly presented and
extended as collections of intertwined contexts and their observables. If
interpreted classically those structures serve as graph-theoretic "gadgets"
that enforce correlations on the respective preselected and postselected
observable terminal points. The method allows the generalization and extension
to other types of relational properties, in particular, to novel joint
properties predicting classical equality of quantum mechanically distinct
observables. It also facilitates finding faithful orthogonal representations of
quantum observables.
