You can apparently do this. Oh my god.

RUMI TAUGHT ME LAST TIME WE PLAYED MCPE CREATIVE

best example i can give on this, is when, before he retired from yt, stampy made an escape room minigame in one of his videos based off of these bookshelves! (i think- i just remembered him using them 2years ago- so don't quote me 100% on that. just look up: "stampylonghead escape room".)

with a book and quill, random fact too: some people have used these to write about big incidents that have happened all over the world that the major uppers like governments and such are tryna hide from us civilian folk. there's a few downloadable maps online where you can find them and learn of these facts! (although because of this, some mc maps are regional blocked as some countries (like russia for one major example) just hate that people can do this and find out.)

(apologies for the major yap. the chiseled bookshelves are both cool and scary to use.)