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Let's see that a real observable with contextuality can exist thus showing that a hidden variable model of QM could possibly be contextual, thus not obeying the premises of the Kochen-Specker Theorem. The definition of noncontextuality given in the reference The Kochen-Specker Theorem is :
«If a QM system possesses a property (value of an observable), then it does so independently of any measurement context, i.e. independently of how that value is eventually measured.»
Let's take a macroscopic spinning object like a pencil with a central spinning axis. It can have a clockwise or anticlockwise sense of rotation when viewed from its top.
Let's define what I call the «relative sense of rotation». Instead of refering to the topview of the pencil for the sense of rotation, we will refer to an observer's Z axis of reference making an angle with the spinning axis of the pencil. We will measure the sense of rotation relative to that axis. In that case, its value, clockwise or anticlockwise, depends upon the angle between the spinning axis of the pencil and the Z axis. Rotate suffisantly the Z axis towards or away from the pencil, as could be done with an astronaut in a weightlessness state, and you change the «relative sense of rotation» of the pencil from clockwise to anticlockwise or from anticlockwise to clockwise.
The measured sense of rotation here is a «contextual» value of the observable I called the «relative sense of rotation». We deal with a real observable with contextuality. I therefore see no reason why hidden variables models in QM should be presumed to be non-contextual. The key of the matter should lie in the three dimensional spatial behavior «perceived» by the measuring apparatus of the quantum phenomenon or particle under study. No «magic» there.