{TAIL ~ The race} 320 extends and converges in width from the second end surface 312 b to {HEAD ~ the vertical notch surface} 318 b 
{ TAIL ~ The race } 320 extends and converges in width from the second end surface 312 b to { HEAD ~ the vertical notch surface } 318 b
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH