wherein one of said waste containers fits into and fills {HEAD ~ each} of {TAIL ~ said depressions} 
wherein one of said waste containers fits into and fills { HEAD ~ each } of { TAIL ~ said depressions }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL