Lie back, and DON'T THINK.
( ( ( ( ( Lie back ) , ) and ) ( ( DO N'T ) THINK ) ) . )
(ROOT (S (S (NP (NN Lie)) (VP (VBP back))) (, ,) (CC and) (S (NP (NNP DO) (NNP N'T)) (VP (VBD THINK))) (. .)))
Stand up and start thinking.
( ( ( ( Stand up ) and ) ( start thinking ) ) . )
(ROOT (S (VP (VP (VB Stand) (PRT (RP up))) (CC and) (VP (VB start) (NP (NN thinking)))) (. .)))