{HEAD ~ a third set} of {TAIL ~ coefficients} equal to −1 extending away from said direction on said second side 
of
{ HEAD ~ a third set } of { TAIL ~ coefficients } equal to −1 extending away from said direction on said second side
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH