A cap covers {HEAD ~ the open top} and has {TAIL ~ a recessed surface} formed therein directed toward the open top 
A cap covers { HEAD ~ the open top } and has { TAIL ~ a recessed surface } formed therein directed toward the open top
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH