It has been found that {HEAD ~ the shape} of {TAIL ~ a rolling rounded brackets} is particularly useful 
of
It has been found that { HEAD ~ the shape } of { TAIL ~ a rolling rounded brackets } is particularly useful
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH