A temple endpiece includes {HEAD ~ a set} of {TAIL ~ recesses} that engage the projections formed on the lens 
A temple endpiece includes { HEAD ~ a set } of { TAIL ~ recesses } that engage the projections formed on the lens
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH