( ( The analogy ) ( ( is ( that ( of ( ( ( ( ( ( the ocean ) , ) wind ) , ) and ) waves ) ) ) ) . ) )
(ROOT (S (NP (DT The) (NN analogy)) (VP (VBZ is) (NP (NP (DT that)) (PP (IN of) (NP (NP (DT the) (NN ocean)) (, ,) (NP (NN wind)) (, ,) (CC and) (NP (NNS waves)))))) (. .)))
The analogy is that of the ocean, wind, and waves.
(ROOT (S (NP (NNP Ocean) (NNS waves)) (VP (VBP are) (ADVP (RB mainly)) (VP (VBN caused) (PP (IN by) (NP (NN wind))))) (. .)))