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