's a rare window on an artistic collaboration . 
(ROOT (S (VP (VBZ 's) (NP (NP (DT a) (JJ rare) (NN window)) (PP (IN on) (NP (DT an) (JJ artistic) (NN collaboration))))) (. .)))
(ROOT (S (VP (VBZ ) (NP (NP (DT ) (JJ ) (NN )) (PP (IN ) (NP (DT ) (JJ ) (NN ))))) (. )))