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