Schwarz lantern
PATHOLOGICAL EXAMPLE DEVISED BY HERMANN SCHWARZ TO DEMONSTRATE THE DIFFICULTY OF DEFINING SMOOTH SURFACE AREA
Yoshimura fold; Schwarz paradox; Schwarz's polyhedron
In mathematics, the Schwarz lantern is a polyhedral approximation to a cylinder, used as a pathological example of the difficulty of defining the area of a smooth (curved) surface as the limit of the areas of polyhedra. It is formed by stacked rings of isosceles triangles, arranged within each ring in the same pattern as an antiprism.