is built on a potentially interesting idea 
(ROOT (S (VP (VBZ is) (VP (VBN built) (PP (IN on) (NP (DT a) (ADJP (RB potentially) (JJ interesting)) (NN idea)))))))
(ROOT (S (VP (VBZ ) (VP (VBN ) (PP (IN ) (NP (DT ) (ADJP (RB ) (JJ )) (NN )))))))