Push every crate onto a ring. Push, never pull. Swipe, drag, tap a square to walk, or use the pad. Hit par for 3 stars.
Inspect a crate before pushing. Crosses mark floor squares from which a crate cannot reach any goal, even with other crates removed.
A square that can reach a goal may still be blocked by other crates. This checks one push at a time; it does not solve the level.