{HEAD ~ This material} may exit through {TAIL ~ a lower opening} 28 defined by the lower rim 22 
exit through
{ HEAD ~ This material } may exit through { TAIL ~ a lower opening } 28 defined by the lower rim 22
HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH