that burn themselves upon the viewer 's memory 
(ROOT (S (NP (DT that)) (VP (VB burn) (NP (PRP themselves)) (PP (IN upon) (NP (NP (DT the) (NN viewer) (POS 's)) (NN memory))))))
(ROOT (S (NP (DT )) (VP (VB ) (NP (PRP )) (PP (IN ) (NP (NP (DT ) (NN ) (POS )) (NN ))))))