okay, i really went crazy with this one. i took the view of the room through the door on the left side of the first library picture i did and reversed it, drawing what the room looked like. its based on a later time, but the same dragon from the first pic. i have him creating a multi-magic probability circle of protection, using all the ones i mentioned for the last pic, plus 3 that i had to add so it had a sort of pattern. these were magics of light, nature and neutrality, shown on the back right wall. the probability part comes from the center not having a specific pattern and therefore, leaving a range of possibilitys.