That looks like the library and I've never seen a mirror in there. Is it related to the Red Book or solving the logic behind actually reaching the end of the library? EDIT: Just saw your post on the other thread.
Also, I think I understand how to use the Empty Jar correctly now... I managed to 'Seal Cloud' then the next step looked vary familiar to what we do with another item... So even though 'Nothing Happened' I'm pretty sure the issue was "Dimensional"
Still haven't managed to experience a real world Festival of Life pregnancy sequence though... I'm pretty sure that and the Broodmaiden real world pregnancy sequence might be all that's left for me on the Female playthrough.
Next I'll be playing the Male playthrough to try experiencing all possible forced feminization methods. When I happen to have enough of a break from coursework of course.