According to {TAIL ~ one preferred embodiment} of this invention, {HEAD ~ centerline} 60 comprises a weld that joins the two layers of flexible sheet 20 
According to { TAIL ~ one preferred embodiment } of this invention , { HEAD ~ centerline } 60 comprises a weld that joins the two layers of flexible sheet 20
REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH