Oh, I just realized that Mari-sensei made a rather glaring mistake in her depiction of how scrolls were stored. Scrolls don't have spines like books do, so there must be a way to easily identify which scroll is which in a collection or a library. There are several ways to do this, but in a library as big as Alexandria it would have been by attaching a ribbon to the scroll handle. The ribbon has an abbreviated title of the scroll that makes it easy for someone to pick out the specific scroll they're looking for from the stack. That scene on page 17 should really be showing ribbons covering all the scroll racks.