 He found himself thinking in circles of worry and pulled himself back to his problem.
( He ( ( ( ( ( found himself ) ( thinking ( in ( circles ( of worry ) ) ) ) ) and ) ( ( ( pulled himself ) back ) ( to ( his problem ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VP (VBD found) (NP (PRP himself)) (S (VP (VBG thinking) (PP (IN in) (NP (NP (NNS circles)) (PP (IN of) (NP (NN worry)))))))) (CC and) (VP (VBD pulled) (NP (PRP himself)) (PRT (RP back)) (PP (TO to) (NP (PRP$ his) (NN problem))))) (. .)))
He got lost in loops of worry, but snapped himself back to his problem.
( He ( ( ( ( ( got ( lost ( in ( loops ( of worry ) ) ) ) ) , ) but ) ( ( ( snapped himself ) back ) ( to ( his problem ) ) ) ) . ) )
(ROOT (S (NP (PRP He)) (VP (VP (VBD got) (VP (VBN lost) (PP (IN in) (NP (NP (NNS loops)) (PP (IN of) (NP (NN worry))))))) (, ,) (CC but) (VP (VBD snapped) (NP (PRP himself)) (PRT (RP back)) (PP (TO to) (NP (PRP$ his) (NN problem))))) (. .)))