Asynchronous Arrows
The asynchronous arrows control (also known as "chasing arrows") is a simple animation used to indicate that an asynchronous background process is occurring; in other words, a process which does not display a dialog box that might contain a progress indicator. For example, the Finder displays asynchronous arrows in the header while it is updating the window. Figure 2-46 shows asynchronous arrows in their various states.Various states of asynchronous arrows
