In one example, the two cores have adjacent ends which are contiguous, and in other cases {TAIL ~ the adjacent core ends} are separated by {HEAD ~ a space} 
In one example , the two cores have adjacent ends which are contiguous , and in other cases { TAIL ~ the adjacent core ends } are separated by { HEAD ~ a space }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD