{HEAD ~ The containers} 12 are shown preferably as {TAIL ~ generally rectangular volumes}, but other suitable volumetric shapes may be used 
are shown preferably as
{ HEAD ~ The containers } 12 are shown preferably as { TAIL ~ generally rectangular volumes } , but other suitable volumetric shapes may be used
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH