( ( Hidden ( in ( the images ) ) ) ( ( is ( ( a kind ) ( of ( ( genetic code ) ( responsible ( for ( their generation ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (NNP Hidden)) (PP (IN in) (NP (DT the) (NNS images)))) (VP (VBZ is) (NP (NP (DT a) (NN kind)) (PP (IN of) (NP (NP (JJ genetic) (NN code)) (ADJP (JJ responsible) (PP (IN for) (NP (PRP$ their) (NN generation)))))))) (. .)))
Hidden in the images is a kind of genetic code responsible for their generation.
(ROOT (S (NP (DT The) (JJ genetic) (NN code)) (VP (VBZ works) (PP (IN in) (NP (NP (NN series)) (PP (IN of) (NP (JJ three-letter) (NNS codes)))))) (. .)))