I built an acoustic LEVITATOR! Making liquid float on air

I'd like to think someday we'll have those things the size of a room and levitating millions of tiny sand sized partices instead of one or two foam beads. It would all be hooked up to a graphics processor in a sort of gaming system that could generate high percision geometric shapes in the levitating sand. This would build a virtual reality environment that you could actually reach out and touch - or could even touch you back. Gaming doesn't get much more immersive than that. I just hope it isn't too many decades ahead of our time.