The circuit board has {HEAD ~ a groove} in a section of {TAIL ~ a surface} of the circuit board 
The circuit board has { HEAD ~ a groove } in a section of { TAIL ~ a surface } of the circuit board
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH