Extending The Kobayashi Fidget

A short while ago, I was playing with a 3D-printed Kobayashi fidget cube.

It’s an excellent fidget and 3D-printed toy. I was looking for something to remix when I found a remixed version that had supports built into the model so that hovering parts were properly supported and unfused with parts that shouldn’t be touching during print. I decided to modify that by adding a few more blocks to it.

The final thing can be found on Thingiverse.

The Requirements

So the next step after deciding what I wanted to modify and the basics of how I wanted to modify it was laying down some basic guidelines:

Modest:
As far as adding more links, nothing stopping me from making a version that adds as many connected cubes as I can fit on the printer bed. But, there’s no reason to go overboard.

Interesting:
I just wanted to add enough extra cubes to allow for various folding options and interesting states. The good news is that the possibilities of folding the fidget cube increase with every extra pair of cubes added.

Printable:
And all this means nothing if no one can print it and produce a good toy to play with. So it should be easy for someone to download the model file and make one.

The Technicals

To make things interesting, to get the most out of the added cubes, I had to be open to the idea of rotating and reorganizing the layout of the cubes. This involved figuring out some simple topology rules (observations of how pieces can-and-cannot interconnect and the implications).

The first observation is that the cubes hinge on an edge.

The second observation is that each cube has exactly two hinges – one hinge to link to a previous cube and another to link to the next cube. This is how a closed chain of connected cubes is formed.

Here’s the kicker though, depending on what edge a hinge is on (we’ll call this the previous hinge), the other hinge (next hinge) is prohibited from being on certain edges. The edges that are prohibited for the next hinge are the ones that share the same vertice as the previous hinge.

I could probably mention more observations, such as what makes the set of cubes as foldable as possible. Although honestly, in the end, it was just trial and error (more on that later).

The Design Process

After figuring out these basic rules, I needed to figure out a configuration. This isn’t really the kind of thing I can figure out in my head. So I made some simple cubes and taped them together with the plan to prototype and iterate.

I started with the original Kobayashi configuration but then added some extra cubes and started moving the tape around, seeing what would give the most interesting options for the end-product.

Fidgetable

When over-glorifying and overcomplicating a fidget, there’s a question of when a fidget stops being a fidget. When does it stop being simple, satisfying, and low-effort – and instead something that requires attention and cognition to play with?
Quite possibly one of the true pointless questions of our time. I’ve hit peak first-worlder.

There are times when I’m rolling it in my hand, and I find myself needing to look at its configuration and making an active decision on how to make the next fold. So I can’t say for sure, but it seems to be in a gray area.

The Locked State

The plan to modify the Kobayashi fidget happened pretty much as expected, and I’ll call it a success – except for one glaring failure…

As simple as the original fidget was, there was always another fold that could be made. While my remixed version offers more variety and options, there is exactly one dead-end configuration. If you make a fold and encounter it, this is a configuration where you have to unfold it because there are no other options.

Maybe the hinges could be redesigned so there’s always a fold that can be made afterward. But for now, I must accept my design sin in shame! :/