Just a small question about annotation characters.

If I understand p. 326 this sequence should be valid :

<IAA>U+723B<IAS> <ne, ko> <IAS> cat <IAT>.

Is this the case ?

If so, does such an annotation character sequence have any application
in Japanese typography ? In other words, does one find double ruby
notation ? I would find it useful for kanji ignorami like me.

If double furigana are sometimes used, are both annotations found
stacked on top of one another or is one annttion found on top and the
other at the bottom of the annotated character ?

P. Andries

P.-S. : I'm still interested by a definition of "in(-)line software"
(http://www.unicode.org/unicode/reports/tr27/)". I know what inline code
or processing could be but I can't quite understand the relationship
with the inline software mentioned here and processing music text.