When I first saw this concept in the movie, Crimson Peak, I didn’t think fore-edge book art was anything mainstream… ever.
Now, I’ve learned that it’s a legitimate book art. (How did I never hear of this, before?)
It’s something I’m considering including in my altered books art, and perhaps other projects.
Another example, from 1801:
Here’s a 1947 video showing one way fore-edge art was added to books:
And here’s a modern artist working with this concept:
For more historical insights, this 28-minute discussion explains the fore-edge tradition and practice in more detail: