Consider a smartphone in daily use. The screen glows brightly, apps respond to touch, and the battery indicator shows remaining power. The device operates smoothly, screen lit and ready.
The battery level drops to the final mark. The screen remains on, still displaying content and accepting input right up to that point.
The threshold crosses at the instant the battery empties completely. Before this moment, the screen stays illuminated and the phone functions. Immediately after, the screen goes black.
Now the device lies silent and unresponsive. No light emits from the display, and no interaction occurs. The phone has entered a powered-off state.
This reveals the boundary passed: from powered and active to dark and still.