[racket] How to get a pict-box into a slideshow?

Robby Findler writes:

 > You probably want to insert a Racket box into the pict box and then type some code in
 > there that evaluates to a pict.

Got it. It works!

 > But I fear you'll be disappointed. The reason I mothballed these (and I had forgotten
 > about the environment variable!) was because they were just too clunky.

I have seen more elegant user interfaces but so far my impression is
that it does its job.

However, I wonder how I can get hold of the pict-box, or at least of
the Racket boxes inside it, from the surrounding slideshow code. What
I want to do is add arrows between the manually positioned Racket
boxes. Is this possible?

Konrad.