private void spawnRandom() {
		Random random = new Random();
		boolean notValid = true;
		
		while(notValid){
			int location = random.nextInt(ROWS*COLS);
			int row = location / ROWS;
			int col = location%COLS;
			Tile current = board[row][col];
			if(current == null){
				int value = random.nextInt(10)<9?2:4;
				Tile tile = new Tile(value, getTileX(col), getTileY(row));
				board[row][col] = tile;
				notValid = false;
			}
		}
	}