{HEAD ~ The components} which define {TAIL ~ the three points} of engagement with the test member are mounted on this frame 
{ HEAD ~ The components } which define { TAIL ~ the three points } of engagement with the test member are mounted on this frame
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH