( ( Simple machines ) ( ( are ( simple machines ) ) . ) )
(ROOT (S (NP (NN Simple) (NNS machines)) (VP (VBP are) (NP (JJ simple) (NNS machines))) (. .)))
Simple machines are simple machines.
(ROOT (S (S (NP (DT A) (JJ complex) (NN machine)) (VP (VBZ is) (VP (VBN described) (PP (IN by))))) (: :) (S (NP (PRP it)) (VP (VBZ is) (VP (VBN made) (PP (IN of) (NP (QP (JJR more) (IN than) (CD one)) (JJ simple) (NN machine)))))) (. .)))
A complex machine is described by: it is made of more than one simple machine.