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