private void PlaceNodes(int HS, XmlNode node) 
	{
		if (HS < 1)
			throw new RuntimeException("HS must be greater than 1");
		if (node == null)
			throw new RuntimeException("node can not be null");
		
		Random PlaceRandom = new Random(System.currentTimeMillis());
		
		int x = (int) (Distribution.getUniformRandom(PlaceRandom) * HS);
		int y = (int) (Distribution.getUniformRandom(PlaceRandom) * HS);
		// System.out.print("("+x+", "+y+") ");
        Coordinate c = new Coordinate(x, y);
		/* check for collisions */
		while (true) 
		{
			if (this.tree.ContainsCoordinate(c)) 
			{
				x = (int) (Distribution.getUniformRandom(PlaceRandom) * HS);
				y = (int) (Distribution.getUniformRandom(PlaceRandom) * HS);
				
				c = new Coordinate(x, y);
			} 
			else 
			{
				this.tree.addCoordinate(node, c);
				break;
			}
		}
	}