Reading this maze
Signal gallery starts at row 6, column 3. Of the 42 grid positions, 33 are paintable and 9 are walls. The start is already painted; the other 32 tiles remain to be reached.
The switch at row 1, column 7 toggles gate A on every entry. Start right; opening the gate changes where later slides can stop. The first slide covers 2 of 33 target tiles; 31 remain.
The verified opening crosses 1 tiles before stopping. A breadth-first search proves a 25-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.