( ( ( ( Enunciated ( ( his principle ) ( ( ( of ` ) ( least time ) ) ' ) ) ) , ) ( according ( to which ) ) ) ( , ( ( ( a ray ) ( of light ) ) ( ( follows ( ( the path ) ( which ( ( takes it ) ( to ( ( its destination ) ( in ( the ( shortest time ) ) ) ) ) ) ) ) ) . ) ) ) )
(ROOT (S (S (VP (VBN Enunciated) (NP (NP (PRP$ his) (NN principle)) (PP (IN of) (`` `) (NP (JJS least) (NN time)) ('' '))) (, ,) (PP (VBG according) (PP (TO to) (NP (WDT which)))))) (, ,) (NP (NP (DT a) (NN ray)) (PP (IN of) (NP (NN light)))) (VP (VBZ follows) (NP (NP (DT the) (NN path)) (SBAR (WHNP (WDT which)) (S (VP (VBZ takes) (NP (PRP it)) (PP (TO to) (NP (NP (PRP$ its) (NN destination)) (PP (IN in) (NP (DT the) (JJS shortest) (NN time)))))))))) (. .)))
Enunciated his principle of 'least time', according to which, a ray of light follows the path which takes it to its destination in the shortest time.
(ROOT (S (NP (NP (NNP Fermat) (POS 's)) (NN principle)) (VP (VBZ states) (SBAR (IN that) (S (NP (NN light)) (VP (MD will) (ADVP (RB always)) (VP (VB take) (NP (NP (DT the) (NN path)) (PP (IN of) (NP (NP (DT the) (JJS least) (NN amount)) (PP (IN of) (NP (NN time))))))))))) (. .)))