Fig. 8From: Do Leonardo da Vinci’s drawings, room acoustics and radio astronomy have anything in common?Outdoor installations erected to demonstrate acoustic curiosities. a Contemporary outdoor installation made by 3D printing [15,16,17], photo courtesy of M. Kladeftira. b Eighteenth-century Whispering Grottoes in Oliwa Park, Gdańsk, Poland [10, 14], photo courtesy of T. StrugBack to article page