Quarto
Popular board game of deductive reasoning.
You can play the standard Quarto version where the aim is to line up 4 pieces that share the same attribute (round or square; light or dark; big or small; solid or hollow).
A second variant of the game is 2x2-Quarto where one can win by placing four matching pieces in a 2x2 square.
You can choose between five levels of difficulty.