>> Imagine a choir piece with three women voices, to be notated on two
>> staves to save vertical space. To increase readability in the
>> score it might make sense to position voices 1 and 2 in the upper
>> staff and voice 3 into the lower one. Suddenly the musical
>> structure changes, and it is better to have voice 1 alone in the
>> upper staff and voices 2 and 3 in the lower one. The lyrics of
>> voice 2 should positioned below staff 1 for the former and above
>> staff 2 for the latter situation.
>
> Something like the attached. Not how I would do it, but it gives the
> gist perhaps.
Yeah, something like that. Very nice, thanks!
>> Another example is the strange beast of opera score reductions for
>> piano solo, as done in the 19th century: there are no separate
>> staves for the singers; instead, the lyrics are directly embedded
>> into the piano staves and jump around between the staves as needed
>> (I couldn't quickly find a scan in the internet, sorry).
>
> I've only seen those where the soloists are all on one staff, above
> the piano, arranged like Alice and Eve in the NR. Then they break
> out into multiple staves for trios, sextets, etc.
You can find such scores if you go to IMLSP and look for piano solo
arrangements of operas with 'sublinear text'.
Werner