Built by Leonardo Torres y Quevedo, this was the world's first true game-playing automaton — no hidden human, just electrical relays and mechanical arms.
It plays the King + Rook vs King endgame, a position that can always be won with perfect play. The machine detects piece positions via electrical contacts on the board and moves its pieces with a mechanical arm.
It was demonstrated at the 1914 Paris World Fair and still works today, preserved in Madrid.
Each square lights up when a piece is detected by the electrical contacts beneath the board.