[racket] documentation example for slideshow/pict

That's really funny, Neil!  And congratulations on earning your living
as a racketeer.  And surely you're one of the Racket people who
generally know what they are talking about.  I already said I liked
Racket, because of the integrated editor that even kids love, and so I
can easily edit Latex files on a PC running Shutters.  But you don't
want to answer all my dumb questions, like how do you take 81 picts
and make them into a 9x9 lined table where no entry crosses the lines?
Or: can you include files without a module system?  Eventually, after
Racket really takes off, the Racket maintainers will want the dox to
explain such rudimentary things.  If nothing else, the `Turbo Powered
Lite' books will actually turn folks away from Racket.