https://makezine.com/article/digital-fabrication/3d-printing-workshop/math-monday-star-sphericon/
Math Monday: Star Sphericon - Make:
Jun 27, 2011 - A sphericon is a shape that you get by: (1) rotating a symmetric polygon about a mirror axis to get a solid of revolution, (2) cutting the solid into two equal...
math mondaystarsphericonmake