public ArrayList<Tile> getFreeCells(){
		ArrayList<Tile> freeCells = new ArrayList<Tile>(14);
		for(int i=0;i<getX();i++){
			for(int u=0;u<getY();u++){
				if(this.cells[i][u]==0){
					freeCells.add(new Tile(i,u,0));
				}
			}
		}
		return freeCells;
	}