Here are some example trees to display with the tree program.  First,
the examples from the man page:

(ex1)  \tree (S(NP(John))(VP(runs)))

(ex2)  \tree ((((John)(runs))))

%(ex3)  \tree \- this line will remain unchanged

(ex4) is not given, since it has an error

(ex5)  \tree -q (a phrase composed of others(a phrase
               (a)(phrase))
               This is a comment.(composed) (of others
               (of)(others)) )

(ex6)  \tree ((S(John)(V(runs)(fast))) (==$>$)
               (S(V(runs)(fast))(S(John)(does))))

(ex7)  \tree (S                % Comments like this
                (NP            % are skipped over.
                  (John)
                )
                (VP
                  (runs)
                )
              )

(ex8)  \tree (NP (Det(John's \(genitive\)))
               (N\([+count]\)(legs)) )

(ex9)  \tree (\T S (every) (good boy)
               (VP (\L V(does)) (\L A(fine)) ))

(ex10) \tree (S(PP\O\D(near)(him))(NP(John))
               (VP\M(saw)(a snake)))

Then here are a couple of trees from the sample file Jeff Goldberg
distributed:

(1) \tree
(S (NP[+WH] (Who))
  (S/NP (V[INV] (did))
        (NP (you))
        (VP[BSE]/NP (V[BSE] (see))
                      (NP[NULL]/NP (e))
        )
  )
)

(2) \tree
(S (PP (P1 (P (on))
          (NP (which)
              (N1 (N (table)))
          )
      )
  )
  (S/PP (V (do))
        (NP (you))
        (VP/PP (V (think))
            (S/PP (NP (Martha))
               (VP/PP (V (believes))
                   (S/PP (NP (Irving))
                       (VP/PP (V (put)) (NP (Det (the) (N1 (N (book)))))
                                (PP/PP (e))
                       )
                   )
               )
           )
       )
   )
)

Chris Barker gave these examples (in a slightly different
form):

       \tree
((S (NP (N) (PP (P) (NP)))
   (VP (V) (PP (P) (NP))))

(\I S (\I NP (N) (\I PP (P) (NP)))
   (VP (V) (\I PP (P) (NP)))))

       \tree
(\I\(mutakaatib\)\L
       (u
(u ((C\O)(V)(C\O)))
(a (V) (C\O)
   (V)
   (V))
(i ((C\O)(V)(C\O))))
       )

       \tree
( (C
    (u\I
       (m)
       (\O)    % leave space below first `V' in upper tree
       (g)
       (n)
       (\O)    % leave space below second `V' in upper tree
       (t)
    )
 )
 (V)
 (C ())        % empty node attaches to `g'
 (C ())        % empty node attaches to `n'
 (V)
 (C ())        % empty node attaches to `t'
 ((\O(s\O)))
)

\bye