:cyclone:

doubled-sided material + camera

* stopped: show nothing
* started: fixed camera; show discs
* waiting: move camera; fix camera; form torus of discs and rotate;
* working: move camera; fix camera; form cylinder of discs and shuffle
* success: move camera; rotate camera; stop animation; show sorted cylinder
* error:   move camera; rotate camera; mis-align cylinder
* timeout: move camera;