{TAIL ~ Mobile plaque}, without trapping, presents {HEAD ~ a target} difficult to maintain in contact 
{ TAIL ~ Mobile plaque } , without trapping , presents { HEAD ~ a target } difficult to maintain in contact
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH