In {TAIL ~ the UPC symbology}, {HEAD ~ a character} is defined as having two bars 16 and two spaces 18 of varying widths 
In
In { TAIL ~ the UPC symbology } , { HEAD ~ a character } is defined as having two bars 16 and two spaces 18 of varying widths
REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH