The buses of one layer are connected to the appropriate bus of the other layer using through {HEAD ~ holes} located in {TAIL ~ the array} 
located in
The buses of one layer are connected to the appropriate bus of the other layer using through { HEAD ~ holes } located in { TAIL ~ the array }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL