twirling baton

twirling baton n.  [PLATO] The overstrike sequence -/|\-/|\-
   which produces an animated twirling baton.  If you output it with a
   single backspace between characters, the baton spins in place.  If
   you output the sequence BS SP between characters, the baton spins
   from left to right.  If you output BS SP BS BS between characters,
   the baton spins from right to left.

   The twirling baton was a popular component of animated signature
   files on the pioneering PLATO educational timesharing system.  The
   `archie' Internet service is perhaps the best-known baton
   program today; it uses the twirling baton as an idler indicating
   that the program is working on a query.