public List <SpatialObj <T> > WindowQuery(Rectangle window)
        {
            // Finds objects within a Rectangular range (window)
            List <SpatialObj <T> > answer          = new List <SpatialObj <T> >();
            Queue <CoverNode <T> > searching_nodes = new Queue <CoverNode <T> >();

            searching_nodes.Enqueue(rootNode);
            while (searching_nodes.Count > 0)
            {
                CoverNode <T> current_node = searching_nodes.Dequeue();
                if (current_node.IntersectsWith(window))
                {
                    answer.AddRange(current_node.GetRangeQueryObj(window));
                    if (current_node.HasChildren())
                    {
                        foreach (CoverNode <T> child in current_node.GetChildren())
                        {
                            if (!searching_nodes.Contains(child))
                            {
                                searching_nodes.Enqueue(child);
                            }
                        }
                    }
                }
            }
            return(answer);
        }