Following Faces

We stood from a distance and looked at the faces. We walked to the left and to the right as we looked at the faces. We also lowered and raised our body while looking at the faces. The face is a concave translucent mask. Our eye-brain system has learned that faces are usually convex, that is, curved outward rather than concave. When we walked, the face seemed to turn and follow us wherever we went. When we moved up & down, the face also seems to nod. This makes the entire face appear to be following us.