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