(select
 (bgp
   (triple <http://example.org/ns#x> ?:p ?::?19)
   (triple ?::?19 |http://www.w3.org/1999/02/22-rdf-syntax-ns#|:first ?:v)
   (triple ?::?19 |http://www.w3.org/1999/02/22-rdf-syntax-ns#|:rest ?::?18)
   (triple ?::?18 |http://www.w3.org/1999/02/22-rdf-syntax-ns#|:first ?:w)
   (triple ?::?18 |http://www.w3.org/1999/02/22-rdf-syntax-ns#|:rest
           |http://www.w3.org/1999/02/22-rdf-syntax-ns#|:nil))
 (?:p ?:v ?:w))