( ( Images ( formed ( by ( plane mirrors ) ) ) ) ; )
(ROOT (NP (NP (NNS Images)) (VP (VBN formed) (PP (IN by) (NP (NN plane) (NNS mirrors)))) (: ;)))
Images formed by plane mirrors;
(ROOT (S (NP (NNP Plane) (NNS mirrors)) (VP (VBP work) (SBAR (IN because) (S (NP (DT the) (JJ light) (NNS rays)) (VP (VBP create) (NP (NP (DT a) (JJ virtual) (NN image)) (PP (IN behind) (NP (DT the) (NN mirror)))))))) (. .)))