This is another 3D model of a mathematical game called Nine Men's Morris found in a portuguese locality called Monsanto. It is engraved in granite and has a dimension of 48x45 cm. The stone on which the game is engraved has two holes in opposite sides of the engravement. They were probably used to store game pieces.
You can find it in the following coordinates: 40º02’14.2’’N 7º06’41.9’’W