Match two free tiles that are the same. A tile is free when nothing sits on it and its left or right side is open.
NO MORE MATCHES
No free pairs are left. Shuffle the tiles that are left (it keeps the game winnable), or undo a move.
Morningstar Electric Arcade
ELECTRIC MAHJONG
Mahjong solitaire with NEMA outlets, twist-locks and electrical symbols. Tap two free tiles that are exactly the same to clear them. Clear the board to turn the lights on.