Reading this maze
Corridor relay starts at row 3, column 4. Of the 42 grid positions, 32 are paintable and 10 are walls. The start is already painted; the other 31 tiles remain to be reached.
Diamonds A at row 4, column 4 and row 1, column 7 toggle both barred cells marked A. Start up and stop at row 1, column 4. Both A gates share one state; either A diamond flips both together. The first slide covers 3 of 32 target tiles.
The verified opening crosses 2 tiles before stopping. A breadth-first search proves a 26-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.