The surface area of contact between {TAIL ~ the first and the second layers} can define a frame about the perimeter of {HEAD ~ the reservoir} 
The surface area of contact between { TAIL ~ the first and the second layers } can define a frame about the perimeter of { HEAD ~ the reservoir }
OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD