Two Polyhedra Featuring Regular Pentadecagons

42.5 vertex angles in yellow triangles

This polyhedron has 92 faces: twelve regular pentadecagons, twenty equilateral triangles, and sixty isosceles triangles, each with a vertex angle of ~42.5°. Its first stellation appears below.

yellow triangle vertex angle is 42p5 degrees stellation 1

Both models were created using Stella 4d, software you can try for yourself at

The Moon Unit Proposal

moon unit

I propose that 384,400 km (238,855 miles), the average distance from the Earth to the Moon, be called a “moon unit.” Example: “The mileage of my car is over one moon unit.”

Four Polyhedra Featuring Enneagons

enneagons and octagons

enneagons and kites

octagons enneagons bowtie trapezoids

Dual of Convex hull

Enneagons are also called nonagons; they are polygons with nine sides. I used Stella 4d to make these four rotating polyhedra, and you may try this program for yourself at