Soundbug

Electrical engineers have designed the Soundbug, a mouse-size device that makes an audio speaker out of any flat surface. A rod inside the Soundbug, made of a special iron alloy called Terfenol-D, expands and contracts when it is exposed to a magnetic field generated inside the device. This makes the rod vibrate. The vibrations are then transmitted through a suction cup placed on a nonporous flat surface, such as a window or a tabletop.