23 Mar

Woven GSD

Materials Tools 30 equal-length rods Measuring Tape 32 rubber bands Scissors This is a sequel to a (pre-pandemic) post about weaving a stellated polyhedron. This time, I’d like to show how similar techniques can also be used to create a “great stellated dodecahedron” (“GSD” for short; illustration to the left). The materials are in fact… [Read more]

19 Mar


After seeing Laura Taalman’s inspiring 3d print, it occurred to me that one could also render the edge-to-edge cubical array of dodecahedra contemplated in this earlier post in an analogous way. Plus, I just received a new Prusa SL1 printer, and needed something to try it out on. So after just a bit more tinkering… [Read more]

12 Mar


When I showed this recent post to my friend and colleague Laura Taalman, aka mathgrrl, she suggested that another approach to creating a model of the underlying structure would be to construct the icosahedra themselves (rather than the negative space), except use wireframes of the icosahedra rather than solid ones to avoid obscuring all of… [Read more]

09 Mar


Judging from at least one of the previous projects, Studio Infinity is intrigued with connecting polyhedra edge-to-edge. (Of course, connecting them face-to-face is interesting, too, but that’s pretty familiar from Legos and such; and vertex-to-vertex is the same as connecting dual polyhedra face-to-face.) As you can see in the “blueprint” for the Boxtahedral Tower at… [Read more]

08 Mar


This MathStream post about why an icosahedron inscribes in a cube also shows that a dodecahedron fits into a cube in an analogous way. That raised the prospect that it might also be worth building an “Antidodec” analogous to the Anticos. So I quickly mocked one up in OpenSCAD (here’s the two files you need),… [Read more]

17 Sep

Woven SSD

It’s high time that S∞ got back to its core: mathematical constructions you can build. Here’s an attractive star-shaped polyhedron made with a weaving technique that I am indebted to Jürgen Richter-Gebert for introducing me to. It’s called the “small stellated dodecahedron,” and is one of the Kepler-Poinsot regular polyhedra. (Unlike the usual five Platonic… [Read more]

24 Jul

What’s My Radius?

I recently purchased a large number of styrofoam balls as supplies for an upcoming build (about which I will post later). The plans for that build required the diameter of the styrofoam balls, to pretty high accuracy. Although the balls were nominally 4 1/2 inches in diameter, I had noticed in a craft shop that… [Read more]

10 Apr

Gengzhi Goblets

One might think that having produced prototypes of the Gengzhi Goblets, our work is just about done to produce sufficient quantity (roughly 300 of each) to serve as G4G13 giveaways. The question comes down to materials and expense. If the Gengzhi Goblets are actually to be used as measuring cups, then they need to be… [Read more]

05 Apr


In addition to the main, planned build at the Golden Gate STEM Fair, and thanks to donations of materials from Primed Minds, there was also a do-it-yourself/take-home table at the STEM Fair. Participants produced such towers as this one: However, this column isn’t mainly about the inquisitive fun that participants at the take-home table had,… [Read more]