A large, chunky version of L-Game by Edward de Bono. I wanted something really substantial so I modeled each cube at 30 mm³. The base measures 150x150 mm. I offset the pieces by 0.4 mm to leave plenty of room for the pieces to move around. Each piece is chamfered by 45 degrees for easy printing.

Rules:

On each turn, a player must first move their L piece, and then may optionally move 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.