El Ajedrecista (English: The Chess Player) is an automaton built in 1912 by Leonardo Torres y Quevedo, one of the first autonomous machines capable of playing chess. As opposed to the human-operated The Turk and Ajeeb, El Ajedrecista was a true automaton built to play chess without human guidance. It played an endgame with three chess pieces, automatically moving a white king and a rook to checkmate the black king moved by a human opponent.
The device could be considered the first computer game in history.
https://en.wikipedia.org/wiki/El_Ajedrecista
Leonard Torres build a machine able to play a K+R vs K endgame long before the transistor was invented. Can you build the same machine with your battery-included programming language? Bonus point if your program is able to deliver mate in the theoretical mimimum number of moves.
This looks like a good description of the game:
https://en.wikibooks.org/wiki/Chess/The_Endgame/King_and_Rook_vs._King
King and Queen vs King is much simpler. It's acceptable as an answer if you don't have time for K+R vs K.
I looked up the rules of chess for SDF, before I gave up on it, it is a lot more complex than I remembered it.
Do you know how to checkmate with a bishop and a knight in less than 50 moves? It's not that easy, try it.