@end lilypond
@noindent
-Note that both @code{c:5} and @code{c} produce a C major triad.
+As a special exception, @code{c:5} produces a @q{power chord} only
+consisting of root and fifth.
Since an unaltered 11 does not sound good when combined with an
unaltered 13, the 11 is removed from a @code{:13} chord (unless it