Railroad diagrams, a-la sqlite

Has everyone seen the "railroad diagrams" sqlite use in their docs? http://www.sqlite.org/lang_createindex.html , as
oneexample. 

Would it be nice to have the same sort of format in the postgresql docs? (Yeah, I'm volunteering, if people think
they'rea useful thing, 'cos I think they'd add a lot to our documentation.) 

Cheers,
  Steve