#DIY This is a modular book holder with bookmarks. If you print the base two or more times, you can join them together to create a longer base. The other long pieces are book separator and bookmarks that can slide. If you need more bookmarks, just print and slide them in. If you do not need them, don't print them.

This is printable in a space of 15 cubic centimeters. The components should be printed in sequence and with supports. After clining them you can assemble the book holder.

You may need to modify the clearances of the screws.