The other end of {HEAD ~ the arch block} is supported on a spring in a blind hole in {TAIL ~ the arched notch} 
The other end of { HEAD ~ the arch block } is supported on a spring in a blind hole in { TAIL ~ the arched notch }
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL