Add lines to show flow of information in udc.tex

[stefan11]

[stefan11]

Does not look good. @crysmann, if you want, you may play with this and add it to what is there.

\begin{forest}
sm edges without translation
[{S[\slasch \{ \}]}
  [{NP[\local \rnode{1}{\ibox{1}}]} [what]]
  [{S[\slasch \{ \rnode{2}{\ibox{1}} \}]}%, l sep+=\baselineskip
    [{V[\slasch \{ \rnode{3}{\ibox{1}} \}]} [did]]
    [{NP[\slasch \{ \}]} [you]]
    [{VP[\slasch \{ \rnode{4}{\ibox{1}} \}]}
      [{V[\slasch \{ \rnode{5}{\ibox{1}} \}]} [put]]
      [{PP[\slasch \{ \}]} [on the table, roof]]]]]
\end{forest}
\nccurve[angleA=45,angleB=130]{<->}{1}{2}
\nccurve[angleA=270,angleB=70]{<->}{2}{3}
\nccurve[angleA=45,angleB=130]{<->}{3}{4}
\nccurve[angleA=270,angleB=80]{<->}{4}{5}