Books have an inherit problem of being narrow, heavy and unstable. Unless it’s something like a dictionary it has a tendency to fall over. But humans can be clever, and we’ve come up with something called bookends, as demonstrated by builder SEBASTIAN-Z here. The funny thing is, books are found in classrooms, so you could easily find these classroom bookends in a classroom holding books. It’s too bad there’s not a miniature version of these bookends in the classroom depicted in the bookends, then there would be classroom bookends holding books in the classroom bookends holding books in the classroom…I digress.