a surprising , subtle turn at the midway point 
(ROOT (NP (NP (DT a) (JJ surprising) (, ,) (JJ subtle) (NN turn)) (PP (IN at) (NP (DT the) (JJ midway) (NN point)))))
(ROOT (NP (NP (DT ) (JJ ) (, ) (JJ ) (NN )) (PP (IN ) (NP (DT ) (JJ ) (NN )))))