The compound above has eight components, each of which is a tall, triangular, and off-center pyramid. The one below has three co-centered components: elongated square dipyramids.
I made these using Stella 4d: Polyhedron Navigatgor, which you can try for free at http://www.software3d.com/Stella.php.
In this solid, the quadrilaterals are all squares, and the red triangles are regular. The only irregular polygons are the dark blue triangles, which are obtuse and isosceles. I made this using Stella 4d, which you can try for free at http://www.software3d.com/Stella.php.
I made this using Stella 4d: Polyhedron Navigator. For more about this software, including a free trial download of Stella, I refer you to http://www.software3d.com/Stella.php.
I’ve been making and blogging these birthday stars for well over a decade, and see no reason to stop any time soon. This one is made of four {7/3} heptagrams, shown in blue, with four {7/2} heptagrams shown in yellow. The area of intersection of these two types of star polygon is shown in green. This works to yield a 56-pointed star because (7)(4) + (7)(4) = 28 + 28 = 56.
RobertLovesPi.net 