Apparatus, methods, and other embodiments associated with providing a correlation between a power distribution unit and a device are described. For example, one embodiment provides a stent graft including an occlusive material having a preset, overlapping configuration comprising at least three inverted overlapping layers that are folded over one another. A visual security device, such as an optically variable ink, a special film, or combinations thereof is disposed in the zone on the substrate. The modules float individually or can be connected together to from a floating playground with a variety of recreational implements. Finally, a signal analysis device determines if the first and second devices are co-located. The CPU also determines the use of the computed maximum allowable time period as a maximum error retry time period.