Left my USB key at uni in a computer in room CB10.03.430. The computer is the last computer in the row second from left.
I should probably have turned back to get it immediately when I realised, but by then, I was halfway home.
I went to ask security about it today. The security office is in tower building. They have a white USB key there. Unfortunately, I can't describe it will enough to convince them to show it to me. I know the files that are on there. I could even list them. But I can't describe the thing's physical appearance, and I don't know if they have any idea how to find out what's on it.