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