Reading this maze
Long return starts at row 3, column 7. Of the 42 grid positions, 31 are paintable and 11 are walls. The start is already painted; the other 30 tiles remain to be reached.
Diamonds A at row 1, column 2 and row 5, column 4 toggle the gate marked A. Start up and stop at row 1, column 7. Either A diamond flips the same gate; use a return visit to change the next stopping point. The first slide covers 3 of 31 target tiles.
The verified opening crosses 2 tiles before stopping. A breadth-first search proves a 23-slide finish from this exact starting board; that is a reference target, not a move limit. You may revisit any painted tile.
Switch A is a diamond; gate A has bars when closed and a dashed outline when open. Entering the switch toggles it immediately, including during a slide. If you get trapped, undo or restart; Hint checks the current gate and painted-floor state.