The sidewalls 57 typically define {TAIL ~ an obtuse angle} with the bottom surface 55 of {HEAD ~ the recess} 53 
The sidewalls 57 typically define { TAIL ~ an obtuse angle } with the bottom surface 55 of { HEAD ~ the recess } 53
OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH