Doodles and doilies, non-simple symmetric Venn diagrams
In this paper the author creates a method to construct a non-simple, symmetrical Venn diagram of 11 independent simple closed curves. This answers a question of \textit{B. Grünbaum} [Geombinatorics 8, 104-109 (1999; Zbl 0929.52007)].
scientific article; zbMATH DE number 1839004