I'd like to share this thing I just came upon with a friend who doesn't read English.
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. (Wikipedia)
That WP page has no German version, and I'm having no luck searching the web for anything but black (Schwarz) objects (e.g. polyhedral dice) to buy.
Can you point me to an introductory article in German on the themes in the quote above? It can be a PDF. It can be academic, but suitable for an interested layperson who could digest the quoted sentence.