A sky tube is a textile pipe filled with air from a powerful fan. The air makes the tube move very fast and causes it to change shape. It seemed interesting to me to show the movement of the tube in very slow motion, turning it into a slowly moving sculpture.
In the animation the flags move violently in the wind. The sky tube in front moves slowly, thus creating a nice contrast with the background. It looks as if the sky tube resisits the wind outside and the air inside.