wrought iron was used to construct what light houses?
Entity Entity Entity
m.0gg9054 m.02w546s m.05jxkt
North Reef Light Finns Point Range Light Cape Henry Light
class entity
architecture.lighthouse m.0pf1p
architecture.lighthouse architecture.lighthouse_construction_material
Lighthouse Wrought iron
none none
architecture.lighthouse.construction
Construction
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> PREFIX : <http://rdf.freebase.com/ns/> 
SELECT (?x0 AS ?value) WHERE {
SELECT DISTINCT ?x0  WHERE { 
?x0 :type.object.type :architecture.lighthouse . 
VALUES ?x1 { :m.0pf1p } 
?x0 :architecture.lighthouse.construction ?x1 . 
FILTER ( ?x0 != ?x1  )
}
}
(AND architecture.lighthouse (JOIN architecture.lighthouse.construction m.0pf1p))