( ( If ( he ( used ( ( a dish ) ( shaped form ) ) ) ) ) ( , ( he ( ( would ( get ( a ( convex lens ) ) ) ) ; ) ) ) )
(ROOT (S (SBAR (IN If) (S (NP (PRP he)) (VP (VBD used) (NP (NP (DT a) (NN dish)) (VP (VBN shaped) (NP (NN form))))))) (, ,) (NP (PRP he)) (VP (MD would) (VP (VB get) (NP (DT a) (NN convex) (NN lens)))) (: ;)))
If he used a dish shaped form, he would get a convex lens;
(ROOT (S (NP (NP (DT The) (NN lens)) (PP (IN of) (NP (DT the) (NN eye)))) (VP (VBZ is) (S (NP (DT a) (-LRB- -LRB-) (NN n) (-RRB- -RRB-) (NN convex)) (VP (VB shape)))) (. .)))