I heard a fly buzz

 I heard a fly buzz, 9’x12’x20’-  The large horizontal board slowly raises and l

 I heard a fly buzz, 9’x12’x20’-  The large horizontal board slowly raises and lowers, taps the floor and the ceiling before returning to a balanced position.  Two layers of screen surronding the case create a moire effect when the viewer walks by. Installed at the Philadelphia International Airport. 2009