a designating portion configured to receive {HEAD ~ metadata} defined in {TAIL ~ a range} of all time within the displayable period, the metadata including: 
defined in
a designating portion configured to receive { HEAD ~ metadata } defined in { TAIL ~ a range } of all time within the displayable period , the metadata including :
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH