My first start-to-finish puzzle design is Minimis 2x2x1. There have been countless 2x2x1 implementations so it's not a new puzzle, but my novel mechanism does it with exactly four pieces.

Quick links:

• Available from Shapeways in solid ($40) or hollow ($18).
• Free STL files and OpenSCAD source data at Thingiverse
• YouTube video showing assembly here.
• My blog archive showing development of the model here.

The idea was indirectly inspired by a sketch by Sigurd (Doubleyou) in this thread viewtopic.php?p=171785#p171785

I translated his sketch into a 3D model. It was nice to see it in solid form, although I didn't really think it was practical because there was no way to put it together.


Last month I was suddenly inspired to build a different version based on spherical parts linked into a spherical cavity. The first version worked well enough to confirm the concept, but was terribly unstable. I went through four revisions, adding a stationary ball to stabilize the corners, two posts to guide the pieces, and built-in caps to hold them in.


The 'hollow' version I had uploaded to Shapeways had too much filleting, which exposed the hollow centers. So I modified it and built a test copy in clear PVC to test it. (I uploaded the latest version yesterday--apologies to anyone who bought the blemished version before that!)

Not only did the PVC model confirm the design, it looked unexpectedly cool. I don't even want to put stickers on this!


Another cool thing about the clear model is you can view the mechanism by holding it up to the light. Remember, there are only four pieces in total.

I love how it goes together! And at $18 I might order one!

What a great idea and how lovely to still see the mechanism in the transparent version.

Geert

That's a very clever idea, very simple design.

The transparent version is really beautiful. Can you buy a transparent at Shapeways? Maybe you can use stickers similar to the ones Smaz uses for his Dino Cylinder (http://twistypuzzles.com/forum/viewtopic.php?f=15&t=17208&start=0)

Very cool puzzle!

Alex

the beauty of this mechanism is that it only uses the four pieces. That was my initial idea! you can say I came up with a basic mech then VWP just applied the vmech/ sorta to it. Can I say that?

as a gesture he have given me a bunch of prototypes. and the one with spherical cuts is amazing. The pieces just flies around. Not unstable at all ( and it cant come apart!), but VERY loose.

I am really happy how this turned out!

if you ever wanted a 2x2x1, then get this one!

Sigurd

I actually may buy this shortly, but I would want it in black. Because I no absolutely nothing about ShapeWays, how would I do that? Do I have to select Black, Strong and Flexible in the side?

Ostensibly if you select black strong and flexible as the printing material you're going to get a black puzzle

Right, I was just checking as it adds on another $6, so I wasn't sure if that was the correct way of doing it.

I don't like the pricing for black strong and flexible. On some puzzles, it adds as much as $30 to the price. But that's because they just print the parts in white and then dye them, so it takes extra work compared to the white version.

Which Cubesmith stickers would fit ideally?
Shapeways says for the model:
Size of this model:
Size Height 2.7 cm Width 9.1 cm Depth 2.8 cm

The size that Shapeways says is totally irrelevant as those dimensions do not represent actual puzzle size. It's just the size of the four parts together, in the way they are positioned in the STL file.

Regular 3x3x3 stickers will probably fit fine. The size of the STL file in the longest direction (91mm) is equal to four times 19mm (3x3x3 cubie size) plus three 5mm gaps. That would make sense.

I've ordered it in black, strong, flexible. Because Shapeways has informed me that the minimum order is $25, I've switched from white to black (what I prefer anyway) at practically no additional costs.

Wow, very innovative! I like the way that you use the flexibility of the material. And the transparent version is great. You should consider hollow stickers, so one can keep seeing the mechanism through the stickers.

Oskar

Minimis, a puzzle of maximum efficiency in terms of design, looks and transparency!




Pantazis

Are you suggesting that this should be entered in the puzzle design competition?

Thanks for the feedback. I expected people to admire the pretty transparent version, but I hadn't expected much praise of the mechanism itself!


No, Shapeways doesn't offer material that's sufficiently transparent and sufficiently flexible. Objet's specifications say their Transparent Detail material (Fullcure 720) can "withstand bending" so I built one to test it. The test part was already broken when I got it, at lower-left in the picture below. It also wasn't very transparent.



I sized it to accept standard Rubik's 3x3x3 stickers. I measure the finished model at 19.1 mm cube-size, just a hair thicker than my target.

Shapeways gives measurements for the build envelope, the volume occupied in their machine. It includes the space between the individual parts, and Tom correctly figured out exactly how I'd spaced them. Clever!



You certainly played a pivotal role, but I politely decline to compare it with the V-CUBE mech. The only connection is the visual similarity of the sphere-shapes, but that's just a coincidence.

TomZ was the other catalyst for this puzzle. I was working on a sketch for my conjectured Sigma mechanism when TomZ PM'd me a reminder of this model I'd built of Doubleyou's mechanism. TomZ's message inspired me to test some of my ideas on the 2x2x1.

At the outset I regarded this as a "throwaway" project, since there are already so many 2x2x1 schemes out there. But it was a valuable learning experience because it let me conceive, build, and refine a new mechanism in only four days. Shown below are the four mechanisms I tested, from left-to-right. I've continued to make cosmetic changes (hollowing, fillets, etc).

Thanks, that inspired some interesting ideas to explore. The mechanism doesn't need to be completely enclosed, so I could expose parts of it.

I'll keep tinkering!

Great work! I really love the complex simplicity of this puzzle. (I'm hoping you can say it like that.. )

I have enjoyed reading your blog, looking at the close ups, and learning the design stages of a new very ingenious mechanism. Thank you. Very impressive.

So uh, do you think you'll ever try to extend the mechanism to an 8-piece 2x2x2? It looks like it could probably work, although I don't know if it would hold together so well.

Not exactly.

This mechanism has several features that just won't scale up to higher-order cube, but it was inspired by my own Sigma Six mechanism which I had originally conjectured for building a minimal 152-piece 6x6x6. My Sigma concept is unproven but it can be scaled down to an 8-piece 2x2x2, so logically that's what I should build next.


You received a solid model. The 'solid' models exhibit that speed-turning property but the hollow models just slide along with a little friction.

Don't get me wrong. The hollow models turn okay, but they sure don't race around like the solid ones do.



The 'black' material is more of a dark-charcoal gray. Here's what it looked like on an earlier test sample.

Really, really clever.
What's next? A 2x2x1 with only 3 pieces?

Thomas

if I were to call next, I would say the 2x2x3. actually my idea was to create a new 2x2x1 mech, and then add the next layers to make a new 2x2x3 Not very hard.

This is great I can't wait to see your 2x2.There will finally be someone to compete (legally) with v-cube if you can get it up to a 6x6x6.

How about using this as the basis for a 2x2x3? That should be straightforward.

Incredible elegant design, especially that you managed to solve the problem of how to assemble it, but not take it apart, and with just 4 pieces!

Okay, yeah. Honestly, that was my original plan, but I designed this as a learning project for OpenSCAD. The 2x2x1 code is relatively elegant in OpenSCAD because all the geometry is centered around the origin, but things got really cumbersome when I tried to extend it to a 2x2x3 and I just ran out of patience. I promise you my 2x2x3 mechanism is quite unusual, too!

So I've got to choose: 1) start over in a more versatile CAD program, or 2) force myself to invest a few more hours cumbersomely adapting my OpenSCAD model.

Still, anyone interested in solid modeling ought to take a quick look at OpenSCAD. It's no substitute for advanced CAD tools like SolidWorks, Alibre, or Inventor, but it's useful in its own way. You can even download and edit my code for the 2x2x1 model (sans fillets) from Thingiverse.

I am really Hoping it would be sell on Meffert's too!!! it has original mechanism inside so its good to be mass produce



Norman

I agree, you should definitely try to get these mass produced by mefferts.Although I don't have any experience in selling designs,with such an innovative mech and supposedly great turning, it shouldn't be a problem.Do whatever you want to, but in my opinion you should GO FOR IT!

If someone wanted to order a solid transparent one just like in your above pictures how could they do that? Apparently you have a source other then Shapeways and I'm curious of we could you that source too.

Also dare I ask what happens when you try to take an assembled one apart? I think I can guess...

Carl

All my PVC models were built on a Solido SD300 Pro that I currently have in my possession. That allowed me test and refine the mechanism very quickly, as I described above.

I didn't intend to build and sell any puzzles myself; that's why I made them available from Shapeways. I'm reluctant to accept orders for models because I want to concentrate on my next puzzle, but I'll think about auctioning my test samples.

As for disassembly, several people have successfully disassembled the puzzle without breaking it. (Once by accidentally dropping it on a concrete floor.) It's sure not as easy as putting it together, but it can be done.

Wow that printer is pretty cool and I thought a reprap printer was impressive.If you don't mind me asking how much did it cost.You don't have to give an exact cost but an estimate(i.e between $1000 and $3000) would be nice.Also is the printing material expensive

google is your friend,

not directly from the company but this is a price from some where else

http://store.javelin-tech.com/Store-Catalog/Solido-3D-Printer

You can get a great comparison, including price ranges and features, in this chart. It includes RepRap, Fab@Home, and HP's recent DesignJet offering (which is really a rebranded Dimenstion uPrint).

Thanks for the chart it was very helpful . Just on more question though,first are those pieces smoothed,second do the pieces respond well to smoothing.

That's cute; "just one more question" followed by a second question. Honestly, people probably have lots of questions about the technology so I should start a topic specifically for the SD300 as a followup to Jason's earlier discussion at viewtopic.php?f=4&t=15590&start=0

The pieces have been solvent-treated with Weld-On 2007, but not smoothed per se. PVC is not a gel, so solvent doesn't make is smooth out the way ABS does. I treated it with Weld-On to seal any cracks, loose edges, and strengthen it. The solvent increased the sheen on the sidewalls of the part at left but it didn't smooth the surface texture. More on that later.

VeryWetPaint: READ THIS

You're awesome.

I've received my black Minimis today. (BTW, TomZ has written that Shapeways builds a black version in WSF first and dyes it afterwards. The price difference was almost zero, because there is a minimum order volume of $25 at Shapeways).
Incredible fast delivery via UPS. Very nice - easy to assemble. I have it perfectly stickered with ordinary Cubesmith 3x3x3 stickers. A transparent version, showing the ingenious minimalistic mechanism, would be wonderful.
The solution method is almost identical to the 1x1x1.

Too late, I made a 2x2x13 out of this lol... Only one last thing before I can publish it... It has to be printed

Greg

Aha! Then I'm still in the lead...

...I've got three working models already printed! But I don't plan to go beyond 3 layers, so you'll overtake me soon enough.

How to solve it??

Per

. I don't have any material to make one. Can you send 1 for me as a present? I like it.
Just a joke!
Good job VeryWetPaint!

I made a 2x2x1 with 'your' mech a long time before you, so you are not the first but it's not stickered yet...

Will you be uploading the 2x2x3 to shapeways?

Why should anyone be interested in a printed 2x2x3 when a commercial one is available?

Quite so. I intend to upload it to Shapeways so I can test my work in SLS because this is basically my first mechanism and I need the experience.

But candidly, I agree there's not much reason anyone else would choose to buy a prototype if they're looking for a 2x2x3 puzzle. The mass-produced model will always be less expensive, pre-assembled, and better-functioning.

Yes sure, for personal learning it's great. My post was directed the the person above me as I can not understand why somebody other than you would want to print a 2x2x3 with your mechanism.

By the way, I just assembled my copy of your 2x2x1 and it works quite nicely. Snapping it together was scary but it works really well.
I ordered the hollow version, and I've got some feedback on that: The open faces detract from the final puzzle. I could have ordered the solid version, but ordering anything that is not hollowed out is against my principles as I don't like wasting money.
I think you should make a version where the faces are closed, but the puzzle is hollow. Shapeways doesn't mind if you do that and you can get a really good price. If I were you, I'd take the solid version and apply the shell command (at least, if you software can do that) to shell it out to 1mm (or less, I think that can be done with this puzzle) while not having any open faces.

I was just wondering

Meffers should make a cheaper one... 30 $ is just too excessive when you can even print a mini 2x2x3 for 25 $ ^^

Greg