Reading this maze
Forked signal starts at row 3, column 4. Of the 42 grid positions, 30 are paintable and 12 are walls. The start is already painted; the other 29 tiles remain to be reached.
Diamonds A at row 5, column 4 and row 1, column 5 toggle the gate marked A. Start down and stop at row 6, column 4. Either A diamond flips the same gate; use a return visit to change the next stopping point. The first slide covers 4 of 30 target tiles.
The verified opening crosses 3 tiles before stopping. A breadth-first search proves a 19-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.