Each adhesive cluster includes a perimeterless grouping of {HEAD ~ discrete} spaced apart {TAIL ~ adhesive droplets} 
spaced apart
Each adhesive cluster includes a perimeterless grouping of { HEAD ~ discrete } spaced apart { TAIL ~ adhesive droplets }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL