credit to Govoni for the banner

The downside to living in a magical castle is that sometimes strange things happen. Case in point: one of the former Ancient Runes classrooms has whimsical ideas about when exactly it should appear. Currently the door appears in the wall at six pm every Tuesday evening and remains until around 8am on Sunday morning, whereupon the door vanishes from the wall and instead opens out somewhere on the floor above. The door has a brass sign 'Classroom 6B' permanently attached to it, regardless of exactly which wall it appears in (as an aside, it also appears in a few other locations after curfew but as students should be abed this knowledge is not at all common).

The interior of the classroom is relatively unremarkable in that it is a classroom with desks and everything, though admittedly slightly dusty from disuse. The windows, however, aren't always present either, and if there is a pattern to that, Professor Beryl hasn't yet figured it out. As such, around where the window frames ought to be, she has engraved various runes and charmed them to illuminate the room when natural light cannot.

Given that the room often changes its 'schedule' apparently on a whim, Professor Beryl has opted not to use it as her standard classroom. She does however allow students to make use of it as a study space, just beware that the classroom might not let you out in the corridor from which you entered it....