I saw a teacher today with a piece of chalk tied to the end of a string (for drawing circles and such on a chalk board) swing the string around, and the string wrapped around his finger and the string became shorter until there was no more string left. His finger was pointed parallel to the floor so that the plane that the string spins in is perpendicular to the floor. Is there a name for this sort of thing? Is this used in physics problems or anything like that? I'm just interested in more information about this specific situation.