-- Case 5: parent is red, but uncle is black. Path to focus node is either L,L
-- or R,R
balance (Node nv nc nl nr, (Path L pv Red pr):(Path L gv gc u):path) =
  (Node nv nc nl nr, (Path L pv Black (Node gv Red pr u)):path)
balance (Node nv nc nl nr, (Path L pv Red pr):(Path L gv gc u):path) =
  (Node nv nc nl nr, (Path L pv Black (Node gv Red pr u)):path)
balance (Node nv nc nl nr, (Path L pv Red pr):(Path L gv gc u):path) =
  (Node nv nc nl nr, (Path L pv Black (Node gv Red pr u)):path)