( This ( ( is ( ( the shape ) ( of ( a ( convex ( ( -LRB- ( or ( converging -RRB- ) ) ) lens ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This)) (VP (VBZ is) (NP (NP (DT the) (NN shape)) (PP (IN of) (NP (DT a) (JJ convex) (PRN (-LRB- -LRB-) (CC or) (ADJP (JJ converging)) (-RRB- -RRB-)) (NN lens))))) (. .)))
This is the shape of a convex (or converging) lens.
(ROOT (S (NP (DT A) (NN convex) (NN mirror)) (VP (VBZ is) (VP (VBN shaped) (PP (IN like) (NP (NP (DT the) (NN outside)) (PP (IN of) (NP (DT a) (NN bowl))))))) (. .)))
A convex mirror is shaped like the outside of a bowl.