{HEAD ~ None} of {TAIL ~ these three elements} are in contact with the test contact member when the latter is in its rest position 
{ HEAD ~ None } of { TAIL ~ these three elements } are in contact with the test contact member when the latter is in its rest position
HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH