Twinned bows, not to be confused with supernumeraries, do not have an agreed explanation but they could be produced by non-spherical raindrops or ice spheres.
(1)	Imaged by Vincent Jacques (site) at Breil in the French Alpes-Maritimes, 5th May 2004.
(2)	Serge Vasseur (site) saw these bows on July 17, 2004 (sun 15.5° high) at Presles, France. The bows occurred after a thunderstorm ending with heavy rain, small transparent hailstones and some scattered snowflakes.
(3)	Imaged by Eva Seidenfaden (site) at Trier, Germany on Sept 11, 2005. The secondary bow is not split - in agreement with simulations from non-spherical water drops.
	Images are the copyright of the individual photographers and shown here with permission.