Ever heard of marking rune?
It's a spell that creates a sign, and it doesn't work. You can create the sign (or at least i think you still can) and its a bigass bloody wooden posterboard that gets in everyone's way and causes nothing but bother if you cast them in the ocean.
But you can't write on them, or anything. Making a little signpost around the size of the posts on classic graal tiles would be rather cool though
