The L game is a two-player game played on a board of 4×4 squares. Each player has a 3×2 L-shaped tetromino, and there are two 1×1 neutral pieces.

Rules ==================================================================== On each turn, a player must first move their L piece, and then may optionally move either one of the neutral pieces. The game is won by leaving the opponent unable to move their L piece to a new position.

Pieces may not overlap or cover other pieces. On moving the L piece, it is picked up and then placed in empty squares anywhere on the board. It may be rotated or even flipped over in doing so; the only rule is that it must end in a different position from the position it started—thus covering at least one square it did not previously cover. To move a neutral piece, a player simply picks it up then places it in an empty square anywhere on the board.

-Wikipedia https://en.wikipedia.org/wiki/L_game

For assembly you also need 30 magnets with a diameter of 5mm and a height of 2.7mm.