@Override
	public TileSet getBorderOf(int aX, int aY)
	{
		TileSet tiles = new TileSet(this);
		if (getTile(aX - 1, aY) != -1) tiles.add(Tile.create(aX - 1, aY));
		if (getTile(aX + 1, aY) != -1) tiles.add(Tile.create(aX + 1, aY));
		
		final int y = (aY + aX) % 2 == 0 ? aY + 1 : aY - 1;
		
		if (getTile(aX, y) != -1) tiles.add(Tile.create(aX, y));
		
		return tiles;
	}