private void copyGrid(ContentCase grid[][]){
        if(this.grid == null){
            this.grid = new ContentCase [grid.length][grid[0].length];
        }
        for (int i = 0; i < grid.length; i++)
            for(int j = 0; j < grid[0].length; j++)
                this.grid[i][j] = grid[i][j];
    }