The group of parallel metal lines in the horizontal direction of the crossbar structure may be realized by stacking alternating layers of {HEAD ~ metal} and {TAIL ~ insulator}, patterning the stacks into stripes, and etching vertically to form mesas that include stacks of isolated horizontal metal lines 
The group of parallel metal lines in the horizontal direction of the crossbar structure may be realized by stacking alternating layers of { HEAD ~ metal } and { TAIL ~ insulator } , patterning the stacks into stripes , and etching vertically to form mesas that include stacks of isolated horizontal metal lines
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH