an enjoyable , if occasionally flawed , experiment . 
(ROOT (NP (DT an) (ADJP (ADJP (JJ enjoyable)) (, ,) (SBAR (IN if) (FRAG (ADJP (RB occasionally) (JJ flawed)))) (, ,)) (NN experiment) (. .)))
(ROOT (NP (DT ) (ADJP (ADJP (JJ )) (, ) (SBAR (IN ) (FRAG (ADJP (RB ) (JJ )))) (, )) (NN ) (. )))