A wall is formed in {HEAD ~ the bottom ply} which defines a well into which {TAIL ~ a fragrance sample} is deposited 
A wall is formed in { HEAD ~ the bottom ply } which defines a well into which { TAIL ~ a fragrance sample } is deposited
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH