{HEAD ~ The lower surface} and {TAIL ~ the upper surface} of the clasp do not run parallel to one another 
{ HEAD ~ The lower surface } and { TAIL ~ the upper surface } of the clasp do not run parallel to one another
HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH