( It ( ( was ( used ( of ( ( a ship ) ( ( ( ( on ( ( the crest ) ( of ( a wave ) ) ) ) , ) and ) ( of ( fortifications ( with ( high walls ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBD was) (VP (VBN used) (PP (IN of) (NP (NP (DT a) (NN ship)) (PP (PP (IN on) (NP (NP (DT the) (NN crest)) (PP (IN of) (NP (DT a) (NN wave))))) (, ,) (CC and) (PP (IN of) (NP (NP (NNS fortifications)) (PP (IN with) (NP (JJ high) (NNS walls)))))))))) (. .)))
It was used of a ship on the crest of a wave, and of fortifications with high walls.
(ROOT (S (NP (NP (DT The) (JJ high) (NNS points)) (PP (IN in) (NP (DT a) (JJ transverse) (NN wave)))) (VP (VBP are) (VP (VBN called) (NP (NNS crests)))) (. .)))