Pictures first. Explanation and notes to follow. Anybody guess as to what mechanism is inside yet?



(The rest are deliberately just picture links so as to make the page load quicker)

http://chrono.org/puzzles/3x4x4/3x4x4-1.jpg

http://chrono.org/puzzles/3x4x4/3x4x4-2.jpg

http://chrono.org/puzzles/3x4x4/3x4x4-3.jpg

http://chrono.org/puzzles/3x4x4/3x4x4-5.jpg

http://chrono.org/puzzles/3x4x4/3x4x4-6.jpg

I had been hoping to take this puzzle to the competition today in San Diego (technically yesterday I suppose) but I got tied up with another project and only finished stickering and whatnot about one hour ago (rather than sleeping...).

The mechanism is a.... ...

It turns pretty smoothly although due to the tight clearances internally it does bind occasionally. This will eventually be smoothed out, but I'm just happy to have it in one complete piece for the moment. I did have to re-do the interior thoroughly once, however, which basically cost me about 6 hours of Time. All told, this puzzle has probably taken me... 40 hours or so to build. Granted now that the experimentation is done, a focused individual could probably do one in half the hours. But I'm a pretty slow worker.

This has also been my most challenging puzzle build to date. Regardless however, the 3x3x4 is still my favorite. Sorry, 3x4x4...

I guess you can build this from an East Sheen 4x4x4, but knowing your skills, it wouldn't surprise me if you made this from a regular 3x3x3, just like you did with your 3x3x4.

Congratulations! It looks perfect!

Thomas

Thomas took the words out of my mouth.

Once again, you amaze me greatly.


Any word on those mod demonstration videos?

Ok, for the curious, here is an internal shot of the 3x4x4 during the construction process. I will provide more thorough details later of course, but this should at least satisfy some curiosity. So make a quick guess and then go to the URL:

http://chrono.org/puzzles/3x4x4/3x4x4-inside-1.jpg


Now for a few spoiler notes regarding the picture above. Use your mouse cursor to highlight the text for more info:

Start Spoiler:
Obviously then the mechanism at the core is an Eastsheen 4x4x4. The Eastsheen is 60mm across and it needed to be fit into a space less than 57mm. In fact, that space would have to be less than approximately 54mm. What's more, if you want to make sure that the puzzle will actually rotate, the mechanism needs to be smoothed down to under 53mm just to make sure it clears every part.

Modified piece count
36 Rubik's Cube cubies
8 Rubik's Cube center caps
12 middle layer internal edges
32 outer layer edges
8 outer layer corners
16 internal track blocks
1 modified core

113 modified parts that I can think of.

Reducing the Eastsheen 4x4x4 mechanism to fit inside can be a real challenge. It's hard to explain it without pictures if you've never opened up one of these puzzles before, but it is another case where cutting/sanding too much results in internal pieces popping and not enough will cause binding and possible breakage. Even more so than building a 5 layer Square-1, the margin for error feels like it's even smaller. This tiny bit of error on my first go-around meant I had to throw away 16 pieces and make them from scratch again. In total I think I ended up remaking about 22 pieces.

To the best of my knowledge it is not possible to build a 3x4x4 using standard Rubik's Cube pieces using a regular 3x3x3 core. The corner pieces are already at the limit of comfort on a 3x3x4, I suspect on a 3x4x4 the corners would be completely unsupported and would require exotic methods to retain (magnetics or other pressure type locking/blocking mechanisms).

So in order for the puzzle to stay with my general philosophy of making it buildable with simple hand tools and Time, I went with the Eastsheen even if it wasn't my first choice. Indeed, I stumbled upon the idea to make this while I was in the process of building a 4x4x5. In fact some of the pieces ended up in my prototype, as looking back now, I consider the prototype to be lacking in alignment quality in several pieces.

This is not a puzzle for the impatient! Assembling a 4x4x4 is a challenge enough. Assembling it after turning it into a 3x4x4 was occasionally a nightmare. This puzzle is also very intolerant of alignment errors. The Eastsheen mechanism is not spring loaded, so alignment problems will only lead to premature wear of the parts or possible breakage.

Speaking of assembly... If all you do is glue the pieces on, you will not be able to disassemble the puzzle later. This is a very important point. You HAVE to be able to disassemble this puzzle later. Because of the tight tolerances I mentioned previously, if one internal piece jumps its track, odds are the puzzle will initially feel loose and will probably eventually fly apart. Also a screw could start backing out, which will eventually lead to the same problem. That will be a huge problem.

For this reason I made sure that two center middle caps were removable. They're held in place by pressure alone, using small dovetail joints. Two caps can be popped off so that a screw can be removed and the puzzle safely disassembled.

http://chrono.org/puzzles/3x4x4/3x4x4-inside-2.jpg
http://chrono.org/puzzles/3x4x4/3x4x4-inside-3.jpg

Phew that's about all for now. I'll see about posting pics of each individual modified piece later.

What time did you leave the competition, Jin?

That is an amazing mod. Not only its a 4x4x3, but it is mad with the standard sized cubie parts.

I wasn't at the competition on Sunday. Unfortunately I was tied up until mid-afternoon and didn't really finish the puzzle until that night anyway.

oh and I did try to make a couple of videos earlier tonight... But the videos failed after export from the camera. Might be a codec issue. Anyway I'll work on it.

WOW wonderful! Great job jin. I hope I'll see you with this in some upcoming caltech tournaments. ^^

Ha! I knew it had to be a 4x4x4!

Terrific job, Jin. You must have the patience of a saint.

Another impressive mod, looks great!
=]

Well I have to say after replacing the 16 pieces which I had initially cut too short, I found that it bound a lot internally with the newer, less cut ones. But I finally found a happy medium and this puzzle is actually pretty darn good. A bit stiff, but it's the way I like it. It will eventually loosen up a bit as pieces wear a little bit but this thing is just fun the way it is.

I'm not a very patient person when it comes to having cool toys, honestly. But some things you just have to do right and that takes Time.

Solution:

-Separate the 1x2 centers. Very easy.
-Separate the 2x2 centers. Also very easy.
-Check if the color figuration is correct by looking at a corner. To fix, use the following algorithm.

(Rr)2 U2 D2 (Rr)2

-Pair edges. If you know how to do this on your own, please skip reading the rest of this step. Place an unpaired edge in the UF position. Looking at the left wing, find it's pair piece, and place it in the DB position. Make sure there is another unfinished edge in the UR position. Perform (Rr)2 U' R2 U (Rr)2. If you look, you performed something very similar to edge pairing for big cubes.

-Edge parity . 2 edges left unfixed. I'm not certain if this is possible. I've simulated it on my 4x4 several times, and it didn't come up and I couldn't figure a way for it to happen. I'm fairly sure it isn't, but I'm not certain. Since the puzzle is, when concerning those edges, is restricted to half turns, it is essentially two 2-swaps, so there would never be an odd number of swaps. The three cycle from the previous step is achievable by creating two 2-swaps, altering one of the swaps, then undoing the two 2-swap move, fixing one, but not the other.

-Solve like a Domino (2x3x3). Jaap's site has nice solutions.

-Solve middle layer. Achievable with basic 3x3 knowledge.

I agree completely! Another amazing mod. your skill patience with modifing the cubies is phenomenal!
Lee

My solution is to solve the middle layer intuitively, then pair like a 4x4, then solve like a domino.

It can be done all intuitvely until the final stage, which is just a matter of commutators.

Anybody else think there should be a article in the article section on how to make a 3x4x4 cube and a 4x3x3 cube? I think there should be one there. Anybody one else?

That's always the challenge of writing a tutorial for something like this. Really the most complicated part about the build was how long it took to get everything right and spending a little Time figuring out how things would mesh together properly.

I too think that any builder at this level of the game doesn't really need a detailed tutorial, but would be able to make one as well by just spending some Time glancing at the internal pictures for a while. In my humble opinion though I think there is at most a very small number of people in the community who can pull something like this off using the same method. Maybe 2-3 people at most. This is not a boast, as I'm sure there are thousands of people who could do the same given enough Time and interest in the hobby. It's just that even among the more experienced puzzle makers you will have people who have their specialties in the various mod making categories (3D design, molding, modding, etc). The "modified Fisher" category just happens to be the one I enjoy the most.

What can I say, I'm a zen kind of guy and don't mind the excrutiatingly monotonous hours building puzzles, test fitting over and over until I figure things out.

Ok not really. It's hard work.

Which is easier? Tough to say. The 3x4x4 was a modified Fisher, but the 3x3x4 required a lot internal redesigning. If you're twisting my arm, I'd say... Hmmmm...

I was thinking that the 3x3x4 was more easy to build, just take a domino 2x3x3 and extend it the same way you would with a 3x3x5 ...

Not if you want to make a good 3x3x4. There's just no way you'll get the smoothness and ruggedness with the extended 2x3x3 method which I rejected from very early on. A 30mm core just isn't good enough to support a sturdy 3x3x4.

Great work Jin. This is a massive improvement to the 3x4x4s I made many years ago. I used Master Cubes and simply added bits. I never even cut the cube down so it was absolutely enormous and weighed a ton.