If you've ever noticed the pirate skeletons playing chess in the line for POC, you might realize that they have reached, I believe the term is, endgame. A situation in which there are no legal moves so the game can not end. I'm not sure who created the set up for the pieces (Marty Sklar, John Hench maybe?) but it was an accurate representation of how a game could possibly turn out.
Unfortunately, during one particular refurbishment, Imagineers were cleaning up the scene and moved all of the pieces. No one could figure out where the pieces were supposed to go back. As luck would have it, the original Imagineer had kept meticulous notes and they had been filed away by Disney, including a diagram for the position of the pieces on the chess board.