The basic structure is similar to the old style hand drying systems that were common before cheap folded paper towels or the devices that blow at your damp hands like an asmatic octogenerian. Imagine a backpack with two rollers. On the upper roller is a nice long roll of soft comfy cotton cloth. The lower roller is empty. The cloth is extended over the shoulder of the wearer, through their legs and back up to be attached to the lower roller. When the wearer considers it "time for a change" he (oh it will ALWAYS be a 'he') turns a crank on the backpack, which rolls the soiled portion onto the lower roller while pulling a fresh section down into the area of use. When the clean roll is empty and the dirty full, he just calls a service to come out and change it for him. I expect that this could be an additional service offered by diaper companies. The dirty roll goes away and a fresh one is installed. Ready for another month or two of use!