is plainly dull and visually ugly when it is n't incomprehensible 
(ROOT (VP (VBZ is) (ADJP (ADJP (RB plainly) (JJ dull)) (CC and) (ADJP (RB visually) (JJ ugly))) (SBAR (WHADVP (WRB when)) (S (NP (PRP it)) (VP (VBZ is) (RB n't) (ADJP (JJ incomprehensible)))))))
(ROOT (VP (VBZ ) (ADJP (ADJP (RB ) (JJ )) (CC ) (ADJP (RB ) (JJ ))) (SBAR (WHADVP (WRB )) (S (NP (PRP )) (VP (VBZ ) (RB ) (ADJP (JJ )))))))