The chances are pretty good that not everyone in the gallery will be at the same distance from the sculpture. Using Ultrasonic (Ping) sensors, I could possibly set the sensors to track the closest object/person, or at least limit the range of influence, say, three feet for the head, maybe four for the torso. Or would I want them the same? I'll have to think about that one. If I place the Ping sensors around the neck (for the head movement), they might not interfere with the sensors in the pedestal (for the torso movement). It might look a little.....uhh......punk?