{HEAD ~ The extent} of opening of the sectors 12a and 12b and the count N of the up down counter 42 have {TAIL ~ a pre established relationship} 
have
{ HEAD ~ The extent } of opening of the sectors 12a and 12b and the count N of the up down counter 42 have { TAIL ~ a pre established relationship }
HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL