to let this morph into a typical romantic triangle 
(ROOT (S (VP (TO to) (VP (VB let) (S (NP (DT this)) (VP (VB morph) (PP (IN into) (NP (DT a) (JJ typical) (JJ romantic) (NN triangle)))))))))
(ROOT (S (VP (TO ) (VP (VB ) (S (NP (DT )) (VP (VB ) (PP (IN ) (NP (DT ) (JJ ) (JJ ) (NN )))))))))