Question: What classes of art did the person that said "The noblest pleasure is the joy of understanding." produce?
Answer(s):
answer: Drawing
answer: Painting
answer: Sculpture

SPARQL query:
PREFIX ns: <http://rdf.freebase.com/ns/>
SELECT DISTINCT ?x
WHERE {
FILTER (?x != ?c)
FILTER (!isLiteral(?x) OR lang(?x) = '' OR langMatches(lang(?x), 'en'))
?c ns:people.person.quotations ns:m.048d0t_ . 
?c ns:visual_art.visual_artist.art_forms ?x .
}