It is a game that is like fishing in a barrel, but more stimulating mentally.
( It ( ( is ( ( a game ) ( that ( is ( like ( ( ( ( fishing ( in ( a barrel ) ) ) , ) but ) ( more ( stimulating mentally ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (NP (NP (DT a) (NN game)) (SBAR (WHNP (WDT that)) (S (VP (VBZ is) (PP (IN like) (S (VP (VP (VBG fishing) (PP (IN in) (NP (DT a) (NN barrel)))) (, ,) (CC but) (VP (ADVP (RBR more)) (VBG stimulating) (NP (NNS mentally))))))))))) (. .)))
It is similar to a game of fishing in a barrel.
( It ( ( is ( similar ( to ( ( a game ) ( of ( fishing ( in ( a barrel ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP It)) (VP (VBZ is) (ADJP (JJ similar) (PP (TO to) (NP (NP (DT a) (NN game)) (PP (IN of) (NP (NP (NN fishing)) (PP (IN in) (NP (DT a) (NN barrel))))))))) (. .)))