( ( This structure ) ( ( ( ( is ( very strong ) ) and ) ( produces ( ( an improvement ) ( similar ( to ( ( the difference ) ( between ( ( ( a ( brittle ( pencil lead ) ) ) and ) ( a ( carbon-fibre ( tennis racquet ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT This) (NN structure)) (VP (VP (VBZ is) (ADJP (RB very) (JJ strong))) (CC and) (VP (VBZ produces) (S (NP (DT an) (NN improvement)) (ADJP (JJ similar) (PP (TO to) (NP (NP (DT the) (NN difference)) (PP (IN between) (NP (NP (DT a) (JJ brittle) (NN pencil) (NN lead)) (CC and) (NP (DT a) (JJ carbon-fibre) (NN tennis) (NN racquet)))))))))) (. .)))
This structure is very strong and produces an improvement similar to the difference between a brittle pencil lead and a carbon-fibre tennis racquet.
(ROOT (S (SBAR (IN Although) (S (NP (PRP they)) (VP (VBP differ) (ADVP (RB vastly)) (PP (IN in) (NP (NNS hardness)))))) (, ,) (NP (NP (NN pencil) (NN lead)) (CC and) (NP (NNS diamonds))) (DT both) (VP (VBP contain) (NP (NN carbon))) (. .)))