of using george and lucy 's most obvious differences to ignite sparks 
(ROOT (PP (IN of) (S (VP (VBG using) (NP (NP (NNP george) (CC and) (NN lucy) (POS 's)) (ADJP (RBS most) (JJ obvious)) (NNS differences)) (S (VP (TO to) (VP (VB ignite) (NP (NNS sparks)))))))))
(ROOT (PP (IN ) (S (VP (VBG ) (NP (NP (NNP ) (CC ) (NN ) (POS )) (ADJP (RBS ) (JJ )) (NNS )) (S (VP (TO ) (VP (VB ) (NP (NNS )))))))))