{HEAD ~ Combiner} 18 typically includes a plurality of weighting elements 26 and {TAIL ~ a summer} 28 
{ HEAD ~ Combiner } 18 typically includes a plurality of weighting elements 26 and { TAIL ~ a summer } 28
HEAD HEAD HEAD HEAD HEAD OTH REL REL OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH