An adjustable back leg assembly provides a step ladder of simple construction for {HEAD ~ convenient use} on stairs and {TAIL ~ other sloping surfaces} 
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An adjustable back leg assembly provides a step ladder of simple construction for { HEAD ~ convenient use } on stairs and { TAIL ~ other sloping surfaces }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL