essentially a collection of bits -- 
(ROOT (S (ADVP (RB essentially)) (NP (NP (DT a) (NN collection)) (PP (IN of) (NP (NNS bits)))) (: --)))
(ROOT (S (ADVP (RB )) (NP (NP (DT ) (NN )) (PP (IN ) (NP (NNS )))) (: )))