Thank you for this truly bc I posted pics of my bookcases on Bluesky last weekend, after spending hours taking everything off to move the bookcases, vacuum underneath them, and reorganize, and got so many comments judging me for stacking them that way! Like pls even with the horizontal stacking I had to work miracles to fit all my read books on them 😭 space is a luxury and this is the smartest way of storing them for me.