{HEAD ~ a selector element} having a first input, a second input, {TAIL ~ an output}, and a control signal, wherein: 
{ HEAD ~ a selector element } having a first input , a second input , { TAIL ~ an output } , and a control signal , wherein :
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH