Providing {TAIL ~ signal conductors} which serve only to interconnect {HEAD ~ the programmable logic elements} in each group avoids tying up much longer conductors just to make short interconnections between adjacent programmable logic elements 
Providing { TAIL ~ signal conductors } which serve only to interconnect { HEAD ~ the programmable logic elements } in each group avoids tying up much longer conductors just to make short interconnections between adjacent programmable logic elements
OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH