{HEAD ~ The barcode} has I first columns of modules and {TAIL ~ J rows} of modules transverse to columns 
{ HEAD ~ The barcode } has I first columns of modules and { TAIL ~ J rows } of modules transverse to columns
HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH