GETTY IMAGES HUMANS DANCE. IT'S what they do. Everyone always wants to get some cool new dance move. First there was the electric slide. Yeah, that was cool—but then there was the moonwalk. That was really cool. And now we have the invisible box. OK, maybe it's not exactly a dance move, but more like a trick. The basic idea of this move is to make it seem like the dancer is stepping on a block—a block that's invisible. It's an impressive move, but how does it work?via