Examples of such an activity may be project budget accounting, customer liaison, or oiling machinery during manufacturing.
Since an LOE activity is not itself a work item directly associated with accomplishing the final project product, service or result, but rather one that supports such work, its duration is based on the duration of the discrete work activity it is supporting—oiling machinery will start when manufacturing starts and finish when it finishes.
LOE activities should not have variances either, because they cannot be ahead of or behind schedule based on their meaning.
In a network logic diagram, these two relationships make it look as though the LOE is hanging from the start and finish of the discrete activity.
As a result, an LOE thus diagrammed is sometimes referred to as a "hammock" activity or relationship.