A layer of a resilient and crush resistant polymer is interposed horizontally at any level through {HEAD ~ the entire thickness} of {TAIL ~ the material} of said elements 
of
A layer of a resilient and crush resistant polymer is interposed horizontally at any level through { HEAD ~ the entire thickness } of { TAIL ~ the material } of said elements
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH