At the end of last week John Golden sent me a link that included instructions for how to build a stellated 120-cell from a Zometool set:
here is the direct link to the instructions from David Richter at Western Michigan University:
Stellated 120-cell instructions from David A. Richter
[post publication edit] Also – because there was some confusion about the creation of this object on the Zometool page – as pointed out in the comments below, the original link on Reddit came from StarMuteVII.]
I had some reservations about trying to build this model with the boys because it looked incredibly complicated. Patrick Honner reassured me, though:
Probably the most difficult part was the 24th stet, which involves including 120 long yellow struts. Those struts do not bend very much, so they are a little more difficult to plug in – especially for the hands of a 9 and 11 year old.
So, here’s 5 two minute videos from our 3 day adventure of building this object. The kids enjoyed building the shape and had some interesting observations about the shape all the way through the project:
It was neat to see that my younger son noticed the cubes inside of the dodecahedron in this video. We did another Zome-related project about this fact about a year ago:
A 3D project for kids and adults inspired by Kip Thorne
Overall a really fun project. Lots of fun things to talk about as you build the shape – just make sure to allow a couple of days for this one to be completed!
Mike's Math Page 
Super impressive to me. Please complement the builders!
Probably I mean compliment.
The stellated 120-cell in the Reddit link was created by me. Just clearing that up.
By the way – step 24 was actually fairly easy for me. Step 25 was the most annoying (at the beginning), it got much easier towards the end.
My kids are 11 and 9, so I think they have a harder time bending the struts just because their hands are small. Also, our blue struts are way more flex-y than the yellow struts which made that least step a lot easier.
I can see why that would happen. Did you destroy the model when you were done?
No – it is still sitting in our living room right now! We’ll probably take it apart this weekend.
The intersections of the 2 blues were absolutely horrific for me. Most of my B1s are weak and often come out of the connectors, so putting them all on top became problematic. I eventually had to put 2 of the B1s underneath the B2s instead of on top of them.
We gave up trying to make all of the medium blues fit in perfectly. We managed to get all of them plugged in on at least one side – doubt we could have gotten all pieces in on both sides without glue.
Probably taking apart the model on Saturday.
I am an obsessive perfectionist, so I could not tolerate having any of them connected improperly. I was still unhappy when I got them all in, because on almost every pentagon, 2 of the B1s were underneath the B2s instead of on top.
I doubt I’ll ever take apart the one I constructed. I actually have a bookshelf that is full of Zometool models, though its contents are periodically changing as I cannibalize models that happen to be made of the wrong colors. (It would be really bad if the last part of that sentence were to be taken out of context!) The three very large ones (the 120-cell, 600-cell, and this one) seem to have sentimental value to me.
By the way, I am currently writing a guide for constructing the grand 600-cell. This is being done as I am constructing it, which is a very slow process because we order small kits individually (we don’t have the workshop kit like you do.) When I am done, I’d like to have you and your children try it – it would be a very good way to test if my instructions are thorough enough!
I would like to try to build a few more large projects, but it is harder to commit to something like that just right now. We’ve been home schooling for the last 5 years. On Tuesday, though, the kids will start at the local public schools.
While we were home schooling these larger projects were fairly easy to manage – I had a pretty good feel for how much free time they had and their energy levels. It’ll take a while to see what sorts of projects we can do during the school year.
Hello! This post was recommended for MTBoS 2015: a collection of people’s favorite blog posts of the year. We would like to publish an edited volume of the posts and use the money raised toward a scholarship for TMC. Please let us know by responding via email to tina.cardone1@gmail.com whether or not you grant us permission to include your post. Thank you, Tina and Lani.