http://sploid.gizmodo.com/amazing-scientists-make-things-fly-around-in-space-usi-1492880964 I wanted to ask is there a specific reason for the completely horizontal X shape of the levitated particles. If we already have such precise control over the standing waves, couldn't it be possible to make more unique shapes? Like a 3d one with depth (a bigger thickness, or more levels), or a square pattern with 4 walls and an empty center? Or does it have to be a variation of a 2d star because of the orientation of the speakers? Would 2 more speakers give the X 2 more lines? What about a speaker ring or a sphere? Ultimately that would allow us to control more objects at once independently, and use it in automated construction better.