its metaphors are opaque enough to avoid didacticism , and 
(ROOT (S (NP (PRP$ its) (NNS metaphors)) (VP (VP (VBP are) (ADJP (JJ opaque) (RB enough) (S (VP (TO to) (VP (VB avoid) (NP (NN didacticism))))))) (, ,) (CC and))))
(ROOT (S (NP (PRP$ ) (NNS )) (VP (VP (VBP ) (ADJP (JJ ) (RB ) (S (VP (TO ) (VP (VB ) (NP (NN ))))))) (, ) (CC ))))