Descripción: Each row, column, and tinted square set must have one and only on of each number, character, or sushi piece. Click on the piece you would like to put down on the set on the right. You can also use the keyboard 1-9. Click on the square where you want to place that piece. Hold SHIFT when clicking on the square. This will place a small indication in square. Once you place a piece on that square, all small pencil marks will be deleted.