public void buildSideWalks(int prevSize, int newSize)
	{
		int [] dx = {0, 1, 0, -1};
		int [] dy = {-1, 0, 1, 0};

		int x0 = (getSideLength(newSize)-1)/2, y0 = (getSideLength(newSize)-1)/2;
		for (int d = 0; d < 4; ++d, x0 += dx[d%4], y0 += dy[d%4])
		{
			for (int i = (int)(Math.max(1-prevSize, 0) + (Math.max(prevSize-0.5, 0)*Chunk.lengthOfChunk)); i <= (newSize-0.5)*Chunk.lengthOfChunk-CityHall.height/2; ++i)
			{
				Point2D loc = new Point2D.Double(x0+i*dx[d], y0+i*dy[d]);
				try {
					addBuilding(new SideWalk(), loc);
				} catch (InvalidLocationException e) {
					e.printStackTrace();
				}
			}
		}
	}