{HEAD ~ An intersection} between the upper surface and {TAIL ~ the first and second end surfaces} form first and second cutting edges, respectively 
between
{ HEAD ~ An intersection } between the upper surface and { TAIL ~ the first and second end surfaces } form first and second cutting edges , respectively
HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH