List<List<Cell>> matrix = new ArrayList<>();

        List<Cell> row1 = new ArrayList<>(1);
        row1.add(new Cell(false));
        row1.add(new Cell(false));
        row1.add(new Cell(false));

        matrix.add(row1);

        List<Cell> row2 = new ArrayList<>(2);
        row2.add(new Cell(false));
        row2.add(new Cell(false));
        row2.add(new Cell(false));

        matrix.add(row2);

        List<Cell> row3 = new ArrayList<>(2);
        row3.add(new Cell(false));
        row3.add(new Cell(false));
        row3.add(new Cell(false));

        matrix.add(row3);

        System.out.println();

        matrix.add(Arrays.asList(new Cell(false),new Cell(false),new Cell(false)));




        System.out.println("Size = "+ matrix.size());

        for (int i=0; i<matrix.size();i++){
            System.out.println(matrix.get(i));
        }