An interesting thing I noticed in Sever Hall: A clever auto-doorstop gadget. You know of that sort of double door where one side has to be opened first because it partially blocks the other side? And the problem when the "front" side closes first and blocks the "back" from closing? This problem has been solved in the Engineering Complex. The one door to which it applies has this clever little gadget installed upon it.
It's a lever and a bar. The lever, which is lightly springloaded, is usually held closed by the left door (the one that must be opened second and closed first). When it opens, the bar, behind the right door, opens out- propping the door open. The upshot to this is that the right door can't close until the left one does, ensuring the doors close in the proper order.
I do wonder who came up with that.