I think I understand the basics of piezo crystals. You apply pressure and the crystal produces a voltage. Conversely, you apply a voltage across the crystal and it deforms. My question is this: if you were to apply pressure to only a small region of the crystal (if that's possible?), would the voltage be produced only across that region, or would it spread throughout the crystal? What I'm getting at is the idea of hooking up a number of leads to to the surface of a crystal and getting distinct voltage measurements from different physical regions of the object. Is this a thing that happens? Thanks.