Working on GDP need grob explanation what is a rest?

[Jay Hamilton]

I need to attach a balloon to a rest.
In the current examples I understand how to create a balloon around a stem and 
a note in a chord and presumably around a single note 
\balloonGrobText #'note #' (-4 . -4) \markup { "I'm a note" }
however
r\balloonGrobText #'rest #' (-4 . -4) \markup { "I'm a rest" }
doesn't work so what is a rest in this instance


Yours-
Jay

Jay Hamilton
www.soundand.com
206-328-7694