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