My gift for Gathering For Gardner 11 was a set of pre-cut playing cards that can be used to assemble a cute geometric construction. The final construction looks like this:
It’s a fun design where the interior figure is clearly a dodecahedron, but, since each card represents two faces of the dodecahedron, the symmetry group represented is pyritohedral.
Here is a template that you can print out and cut up to make your own set of cards for this construction.
Your slotted cards should look like this:
You will need six of them to create your ball. Each card should be folded in half “hamburger-style”.
You can join two cards, slotting the two short cuts on one side of one card into two adjacent long cuts on another. All the cards slot into all of the other cards in this same way.
Adding a third card starts to get tricky. The three cards slot together to form a three way join. This is pretty difficult to explain, but here are a bunch of pictures. Don’t worry! Once you have one three-way corner done, the rest are put together the same. By the time you finish, you’ll be a pro!
Now is a great time to take a peek at the inside of your ball before you start closing it up. Can you see the dodecahedron forming?
The rest of this model pretty much follows from the steps previously described. Keep adding pieces like above until your ball is complete! Here are some pictures of the finished ball from different angles.
6 Replies to “Six Card Ball”
that was fun! thank you for the nice gift!
the last card was quite tricky.
Thanks! I’m glad that you liked it and were able to get it put together.
A fun construction! This was the first thing I took out of my G4G11 bag and played with. Thanks.
Thanks! I’m glad that you liked it. I still haven’t done much more than glance through the things in the G4G11 bag. 🙂
I just did it with my own cards using the instructions & template on here. The template printed slightly smaller than my cards (and I didn’t want to mess around figuring out exactly how much I needed to stretch it to print just the right size), so I traced one of my cards on a piece of paper and taped the printed template to the paper. Then I extended the long lines to the edge of the lower sheet, copied the angle of the short line, and translated the short lines to the edge of the larger piece of paper. I used this template to cut out the first card and then used the first card to cut out the rest of the cards because it was more robust.
I think this would be easier with a bit of kerf in the cuts but didn’t bother to make any. When I got my first three-way join, I felt so proud. I had faith that the construction would work if I stuck with it, which it did. Thanks!
Hmm.. interesting that the template printed smaller than the cards, I tried to make the template the standard playing card size. Although, I guess there will always be variations in both card size and printer printing tendencies. Glad you managed to make it work anyways!