  Given the facts that the three-qubit symplectic polar space features three
different kinds of observables and each of its labeled Fano planes acquires a
definite sign, we found that there are 45 distinct types of Mermin pentagrams
in this space. A key element of our classification is the fact that any context
of such pentagram is associated with a unique (positive or negative) Fano
plane. Several intriguing relations between the character of pentagrams'
three-qubit observables and `valuedness' of associated Fano planes are pointed
out. In particular, we find two distinct kinds of negative contexts and as many
as four positive ones.
