Acoustic tractor beam reels in objects like the Death Star
![acoustic tractor beam](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2015/10/ticker_ag_tractorbeam_free.jpg?fit=860%2C460&ssl=1)
A platform tiled with ultrasound-emitting speakers can get small objects to hover, spin, move around and get reeled in as if pulled by a tractor beam (shown).
A. Marzo, B. Drinkwater and S. Subramanian © 2015