How to make reverse animation(keyframes/js)?

Question

css

cube-store.com.ua There is a cube on the site, clicking on which the animation takes place in two stages. But how to make reverse animation? Cube(0) -> Cube(1) -> Cube(2) -> Cube(1) -> Cube(0) -> i. etc.

Answer 1

initially set the active class to the button tag, when clicked, change it to hover, why remove all classes