You could wire a handful of tiny servo‑motors into a ring around the sculpture’s core, all controlled by a microcontroller that reads a heartbeat‑like sine wave from a simple oscillator. The servos twitch slowly, giving a pulse, while a thin sheet of flexible aluminum acting as a resonator inside the frame turns those tiny jolts into a low‑pitched hum. Then drop a few small vibration motors in the corners so that when a user touches the surface, the servos lock into a slightly different phase, making the whole thing sway and “breathe” like a digital heart. Just remember to keep the gear ratios low‑speed; otherwise you’ll end up with a buzzing robot instead of a graceful pulse.