However, it should also be understood that an element may also have {HEAD ~ a variable radial height} along {TAIL ~ the surface} of the element 
However , it should also be understood that an element may also have { HEAD ~ a variable radial height } along { TAIL ~ the surface } of the element
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH