  Several mechanical realizations of PR-Boxes are discussed. Apart from
superluminal correlations, which are known not to be realizable by classical
devices, the requirements (1) PR-condition on input-output relations, (2)
non-signaling, and (3) allowing for independent measurements are discussed
separately. The examples show that internal signaling (inside the box) does not
invariably imply the possibility of external signaling and may externally be
attributed to contextuality. The proposed model requires two classical bits to
be exchanged internally in order to realize the defined requirements. However,
with EPR correlations this can be reduced to one classical bit.
