Documentation bug in 2.1 tutorial

[Bruce J Keeler]

On this page:

http://lilypond.org/doc/v2.1/Documentation/user/out-www/lilypond/Music-expressions-explained.html#Music%20expressions%20explained

The example

       <<
          { a4 g }
          { f e }
          { d b }
       >>

Doesn't appear to be rendering properly.  The image only displays the { a4 g } 
group, but not the { f e } or { d b }.

Unless, of course, I'm completely misunderstanding what the document is trying 
to teach...