An extension node can be defined in a second layer of a software architecture for a first business object existing in a first layer and originally having an association with a second business object that is also in the first layer. The base includes a knee pad receiving portion and roller attachment portions. A sidewall of the inward annular projection and the sidewall of the bore form an annular laser groove open to a cable end of the bore. At a first end of travel of the trolley along the track, the trolley is disposed laterally alongside and vertically offset from the mounting frame such that the space above the mounting frame is unimpeded to permit a user to access the attic space using the deployed ladder. The first television signal is then transmitted to a first display device. It is particularly useful for connections which must be made under vacuum.