Both these angles are substantially the same as {HEAD ~ the corresponding angles} of {TAIL ~ the conventional boot structure} 
of
Both these angles are substantially the same as { HEAD ~ the corresponding angles } of { TAIL ~ the conventional boot structure }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL