{HEAD ~ a first buffer} for buffering {TAIL ~ the positive signal} and outputting a first output signal 
for buffering
{ HEAD ~ a first buffer } for buffering { TAIL ~ the positive signal } and outputting a first output signal
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH