BMW entered existence as a business entity following a restructuring of the Rapp Motorenwerke aircraft engine manufacturing firm in 1917. After the end of World War I in 1918, BMW was forced to cease aircraft engine production by the terms of the Versailles Armistice Treaty. The company consequently shifted to motorcycle production in 1923 once the restrictions of the treaty started to be lifted, followed by automobiles in 1928–29. The circular blue and white BMW logo or roundel is portrayed by BMW as the movement of an aircraft propeller, to signify the white blades cutting through the blue sky – an interpretation that BMW adopted for convenience in 1929, twelve years after the roundel was created. The emblem evolved from the circular Rapp Motorenwerke company logo, from which the BMW company grew, combined with the blue and white colours of the flag of Bavaria, reversed to produce the BMW roundel. However, the origin of the logo being based on the movement of a propeller is in dispute, according to an article posted in 2010 by the New York Times, quoting "At the BMW Museum in Munich, Anne Schmidt-Possiwal, explained that the blue-and-white company logo did not represent a spinning propeller, but was meant to show the colours of the Free State of Bavaria."