Imagine that you’re in a train station. You hear the drone of the public announcement system. And then Julie Andrews begins to sing.

It’s a song from the Sound of Music. Well, that seems weird. But the weirdness is only beginning.

Suddenly, some guy begins to dance. You feel a little uncomfortable. Perhaps he’s crazy. Then, he’s joined by others. First thing you know, they’re all over the place. Could this be spontaneous?