{HEAD ~ The three dimensional crossbar array} may include an insulator layer and {TAIL ~ a metal layer}, or alternatively, a plurality of alternating insulator and metal layers disposed adjacent each other 
{ HEAD ~ The three dimensional crossbar array } may include an insulator layer and { TAIL ~ a metal layer } , or alternatively , a plurality of alternating insulator and metal layers disposed adjacent each other
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH