  A "magic rectangle" of eleven observables of four qubits, employed by Harvey
and Chryssanthacopoulos (2008) to prove the Bell-Kochen-Specker theorem in a
16-dimensional Hilbert space, is given a neat finite-geometrical
reinterpretation in terms of the structure of the symplectic polar space $W(7,
2)$ of the real four-qubit Pauli group. Each of the four sets of observables of
cardinality five represents an elliptic quadric in the three-dimensional
projective space of order two (PG$(3, 2)$) it spans, whereas the remaining set
of cardinality four corresponds to an affine plane of order two. The four
ambient PG$(3, 2)$s of the quadrics intersect pairwise in a line, the resulting
six lines meeting in a point. Projecting the whole configuration from this
distinguished point (observable) one gets another, complementary "magic
rectangle" of the same qualitative structure.
