Combination of Polyhedra

Although da Vinci’s geometric sketches ultimately did not have that great of a mathematical impact, several mathematicians still take inspiration from his work. One such mathematician is George Hart, who combined computer, math, and art in his interdisciplinary research on the creation of new polyhedra. These new types of polyhedra are called symmetrohedra, and the process for generating them is called the “propeller operation.” The propeller operation works by expanding a pre-existing polyhedron and introducing new shapes in the space between these separated faces.

Source (for image and information):

Peterson, Ivars. “Polyhedron Man.” Science News, vol. 160, no. 25/26, 2001, pp. 396–398., doi:10.2307/4012851.