the second design element comprises a groove recessed into {HEAD ~ the interior surface} of {TAIL ~ the body} 
of
the second design element comprises a groove recessed into { HEAD ~ the interior surface } of { TAIL ~ the body }
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL