anchor.diff:          if omnipresent then 
               tree.OmnipresentElements.Remove element |> ignore
           else
  -            if not (SpatialNode.intersectingBounds bounds tree.Node) then
  +            if not (SpatialNode.isIntersectingBounds bounds tree.Node) then
                   Log.info "Element is outside spatial tree's containment area or is not present for removal."
                   tree.OmnipresentElements.Remove element |> ignore
               else SpatialNode.removeElement bounds element tree.Node
   
       let updateElement oldBounds newBounds element tree =
  -        let oldInBounds = SpatialNode.intersectingBounds oldBounds tree.Node
  -        let newInBounds = SpatialNode.intersectingBounds newBounds tree.Node
  +        let oldInBounds = SpatialNode.isIntersectingBounds oldBounds tree.Node
  +        let newInBounds = SpatialNode.isIntersectingBounds newBounds tree.Node
           if oldInBounds && not newInBounds then
               // going out of bounds
               Log.info "Element is outside spatial tree's containment area."
  
positive.code:     let internal atPoint point node =
          Math.isPointInBounds point node.Bounds
  
      let internal intersectingBounds bounds node =
          Math.isBoundsIntersectingBounds bounds node.Bounds
  
      let rec internal addElement bounds element node =
          if intersectingBounds bounds node then
              match node.Children with
              | Left nodes -> for node in nodes do addElement bounds element node
              | Right elements -> elements.Add element |> ignore
  
      let rec internal removeElement bounds element node =
          if intersectingBounds bounds node then
              match node.Children with
              | Left nodes -> for node in nodes do removeElement bounds element node
              | Right elements -> elements.Remove element |> ignore
  
negative.code:         match node.Children with
          | Left nodes ->
              for node in nodes do
                  if isIntersectingBounds oldBounds node || isIntersectingBounds newBounds node then
                      updateElement oldBounds newBounds element node
          | Right elements ->
              if isIntersectingBounds oldBounds node then
                  if not (isIntersectingBounds newBounds node) then elements.Remove element |> ignore
              elif isIntersectingBounds newBounds node then
                  elements.Add element |> ignore
  
      let rec internal getElementsAtPoint point node (set : 'e HashSet) =
  