For all its cry of sadness and rage – at the Orlando shooting tragedy – this music/dance video by Sia, with the dancer Maddie Ziegler, is a call to life. Dance, the ultimate expression of the human body in movement, fills me with wonder and joy. This video is excellent. I know. In my time I have made a number of dance videos, although nothing like this. Filming dance is hellishly difficult, the fixed frame constantly working against the movement, its rigid rectangular shape slicing through the fluid flow of the body.