Jerry Loo's Dirty Dozen and an Opportunity For You

Dirty Dozen, an exceptional puzzle from Jerry Loo.

Hi guys, I have been terribly remiss...I have failed to solve anything in the last week or so! Not for want of trying! My arse has been thoroughly kicked by the Slammed car and even a couple of my twisty puzzle purchases have caused me thorough misery. I have to admit that I am absolutely rubbish at this puzzling stuff - maybe I should give it up? Luckily for me, my good friend and helpful foreign correspondent has chipped in with a brilliant post about a puzzle that I have solved but never gotten around to writing about. Jerry Loo's Dirty Dozen.

Of especial importance just now is that you have a chance to buy a specially made copy of this wonderful puzzle from the great guys at PuzzleMaster via a Kickstarter campaign which they have set up. Their copy of this lovely puzzle will be made in anodised aluminium rather than stainless steel but the three puzzles available look fabulous and are really great value. So without further ado, over to Mike for a wonderful guest post:


Aloha Kakou puzzlers,

The topic of today’s post is designer Jerry Loo’s Dirty Dozen puzzle. Kevin owns a copy and I fully hope and expect that he will chime in liberally on this post, if not add a complete epilogue. In my not-always-humble opinion, it is worthy of extended treatment from multiple perspectives.

For those not in the know, Jerry Loo is an accomplished puzzle collector/designer/blogger hailing from beautiful, tidy Singapore. Jerry began blogging about puzzles in 2011, amidst a veritable explosion of puzzle blogs (e.g. Puzzlemad 2011, Allard's PuzzlingTimes 2011, Gabriel's Puzzle Collection 2010, and Roxanne’s Frustrations 2010). Jerry’s site, recently migrated and relaunched, is what I consider to be one of the Big Four. Check the sidebar and see if you can guess which ones I mean. If Puzzlemad is not in your four, you are dishonourably discharged (Ed - I'm not sure I agree with that...why would anyone read my drivel? Except for the exciting guest posts). Read no further.
How does one get into the Big Four? Launching your blog in the early part of this decade would have helped. Page hits are also clearly an important criterion. You should be approaching a million by now (Ed - amazingly, I am up to 1.28m page views now). That’s not much in this medium, I know, but we are talking puzzles after all. I suppose the main quality that differentiates the Big Four from others is pure consistency over time. Many great puzzle blogs have come and gone over the years. Most start strong but burn out and fade away in short order. Believe me, it’s not easy to do this regularly (Ed - tell me about it!), let alone every single week for nine years like my cherished but possibly deranged editor (Ed - maniacal laughter ensues!). The average person, and even the above-average puzzler, simply can’t maintain the pace. Most of us have full-time jobs, families, and/or cats to attend to. But somehow, someway, Jerry and a few others have managed to maintain consistent output at a very high-quality level for many years. These, then, are the Big Four. I should also mention that some former greats have flirted with revival and some late starters (Alcohol and Alcoves) have achieved greatness in record time. It can be done but requires a demoniac level of enthusiasm and commitment (Ed - or incalculable madness in my case).

Jerry’s  L(8)tice-2. How hard could it be? Very hard indeed. (photo from JL Puzzles)

Beyond his blogging accomplishments, Jerry is also a skilled designer. In fact, that has been his main focus for a while now. I first interacted with Jerry years ago when I was trying to get my hands on Ball in Cylinder, one of his first design efforts. He now has a wide range of designs under his belt in multiple puzzle categories, many of which have gone into limited production. His early efforts with the machined-metal hidden maze type evolved into a focus on packing problems, benefiting no doubt from his association with fellow countryman and esteemed designer/collector Goh Pit Khiam. Presently Jerry is exploring interlocking, assembly, and packing type designs using BurrTools. You can check these out at puzzlewillbeplayed. L(8)tice-2 was, I believe, the first interlocking design to meet Jerry’s characteristically high puzzle quality standard and was eventually produced in stainless by Metallofactura. It is still available now for $43. As Jerry notes, L(8)tice-2 builds on Andrei Ivanov’s Lattice Xi-2, itself inspired by Yoshiyuki Kotani’s ξ-Lattice. Quite a genealogy and I am lucky enough to own the former two. L(8)tice-2 is very tough - my copy remains unassembled to this day (Ed - indeed, mine was sent disassembled and remains that way as well!). Jerry, the designer himself, still uses Burrtools instructions to reassemble...it's that tough. Lattice Xi-2, with fewer pieces and a different release mechanism, is definitely more approachable, but by no means simple to reassemble. It took me quite a while.

The basic piece.

These early design efforts led, in time, to the 12-piece Dirty Dozen. Despite a relatively large number of pieces, Dirty Dozen has an elegance and beauty not found in L(8)tice-2, or most other board-matrix designs for that matter. This is due in large part to the fact that it is composed of only one basic piece. That is correct, all 12 components are identical. This is not nearly as easy to accomplish as it seems. I maintain, based on no actual evidence (Ed - hahaha! We are all entitled to an opinion!), that there are many more ways to construct a self-locking board matrix using irregular pieces than identical pieces. The self-locking quality is critical, and in a way separates the board matrix from the true board burr, which is necessarily held in place via tension. The charm of the board matrix, at least the examples I have played with, lies in its capacity to deform in a rather alarming manner but never throw a board out of the lattice. Dirty Dozen, faithful to this design requirement, is extremely unlikely to come apart. I won’t say impossible, but nearly so. It will take on some interesting rectilinear shapes, threatening always to let lose a piece and shatter the whole edifice. But it never does. As far as I or anyone else has found, there is no way for it to come apart without a very specific sequence of actions (Ed - I have never found any other way to dismantle it).

Deforms pleasingly, but it won’t disintegrate.

The third leg of the stool and the most important quality for any puzzle is, of course, the solution process. Dirty Dozen delivers on this count. The solution is right square in the difficulty sweet spot and, further, rewards one with a deep structural understanding of the puzzle, not simply relief at having gotten it back together. At least for me personally, memorizing a complex movement sequence doesn't really qualify as properly “understanding” a puzzle (Ed - sometimes it's the only way that I manage it!). By this measure, not all puzzles are truly understandable (Ed - aaargh! What about this?). The only downside to an understandable puzzle is that it may have dramatically reduced replay value. That’s the trade-off. But honestly, how many people actually replay (disassemble and reassemble without instructions) highly complex burrs? Not a lot and not very often would be my guess (Ed - don't tell Mrs S, but I rarely replay any of my puzzles once they are understood). Non-understandable puzzles also have replay limitations.

When I ordered Dirty Dozen from Jerry, I had no idea at all what kind of solution it had, nor a clear idea of its difficulty. I asked him (with some trepidation) to deliver it unassembled. I didn’t do this lightly. There is nothing worse than brashly requesting an unassembled puzzle and then having to slink back for the solution a month later. But knowing that the pieces were identical signalled to me that there might be some higher-order logic to this puzzle. I went for it, and am glad I did (Ed - braver than me - or maybe more stupid?).

In most cases, ordering an assembly puzzle unassembled is the clearly more difficult option. You don’t have the advantage of carefully taking it apart, studying the structure at various steps, and even taking photos (I’ve recently learned). However, disassembly can be a significant challenge for Dirty Dozen because of the way it locks. The initial (or in my case final) move to lock the puzzle into shape is certainly not self-apparent. Given the way the puzzle moves, one might be searching in a whole different conceptual area for a long time. Kevin did not have a tough time with disassembly, but he is, of course, a very experienced solver, despite his protestations (Ed - hahahahahaha! Maniacal laughter ensues!).

The pieces (plus eight more).

Assembly for me took about four hours of work over a couple sessions (Ed - OMG!). According to the literature, 23 “moves” are required to fully construct the matrix, in the order 4.2.2.1.3.1.3.2. These sequential solution move counts are largely an artefact of Burrtools design and analysis, serving mainly as a proxy for difficulty level. Useful though this information can be for some puzzles, it can also be classified as inconsequential trivia for others, such as Dirty Dozen for example. It could also be considered a major hint, in some cases.

Although this puzzle has only one possible final configuration, it does have some that are very nearly possible. One such involves the completion of 11 of the 12 pieces. So very close! I got hung up trying to make that work for a long time before I finally gave up and backtracked. Such tantalizing dead-ends contribute significantly to the enjoyment of this puzzle (Ed - you are a sucker for punishment!). The solving experience is generally optimized when there are just enough false assemblies to be challenging, but not so many as to be completely overwhelming. Dirty Dozen straddles this line nicely.

The overall structure of Dirty Dozen is especially notable. Twelve pieces is a pretty high count for a board matrix, with potential for dizzying complexity. It helps to temper this somehow. For Dirty Dozen, this is achieved through the use of identical component pieces exhibiting a very pleasing nested symmetry. The exterior four slots reflect, and the interior two rotate 180 degrees. That second part can be a real help during reassembly. But I think it is particularly interesting how the assembled structure, viewed in plan (90 degrees off the plane on which we observed the component slots), retains these symmetries. The centre has a 90-degree rotational symmetry, and the pair of sides are faithful reflections of one another.

A nice reflection.

An equally nice 180-degree rotation.

Isolating some recurrent symmetries.

Perhaps this was to be expected, and surely it could occur even if the slots were of differing sizes, but I still find it intriguing. I wonder how a designer might play with different configurations of identical pieces, and how far out these symmetries can be extended while still crafting a “good” puzzle. For a case study, check out Goh Pit Kiam’s Partitions, a puzzle I frustratingly missed out on during its initial, and possibly only, JL Puzzles production run.

Back to the solving. Four hours sounds like a long time, and for some puzzles that can seem like an eternity. What makes me so upbeat about Dirty Dozen is that it was legitimately a fun puzzle to work on all the way through. Exploring the way the pieces fit or refuse to fit, and gaining an understanding of the constraints and possibilities was very enjoyable. The false constructions provided a really good challenge and the necessary build-up to the final solution. Some puzzles have singular, ecstatic A-ha! moments, while others like Dirty Dozen offer quite a few small A-ha!'s along the way, and then more of a whoosh of satisfaction when the final piece is placed. What I am trying to say is that this is a really fun puzzle. It has an appeal well beyond the hard-core crowd, in my estimation. It would be a perfect addition to a commercial line (Ed - well that would be coming right up!). On the hard side of the line, but certainly within the ability of the average person with above-average motivation. And the manufacturer only needs to produce a single piece. How efficient is that? Precious few puzzles can translate well to a mass audience and be economical to produce. This might be one of them.

Impassive stainless steel beast.

For the moment, you will need to get your copy direct from Jerry (Ed - this was written and sent to me just before PuzzleMaster decided to start a Kickstarter campaign). He has produced several colourful, affordable, acrylic versions, but I was very happy that he made the extra effort to produce Dirty Dozen in stainless steel (Ed - me too! I lurve my copy!).

It is especially impressive to stack the identical pieces like this

I highly recommend that all serious puzzlers and collectors get this version. It is delightfully hefty at 640grams and is completely indestructible. You could run this puzzle over with a tank and I’m sure it would survive intact. No exaggeration. Let's just hope Dirty Dozen gets back on the market in the not-too-distant future (Ed - no sooner said than done!). Partitions too, for that matter, because I really need that puzzle.

To conclude, Dirty Dozen is a great design and a winner on all levels. I have not played with all of Jerry’s many designs, but I will go out on a limb and claim that this is among his best. It exhibits a blend of qualities that all designers aim for, but so rarely achieve—meaningful structure, simplicity, elegance, and that elusive difficulty sweet spot.

Ok, Kevin, that’s all I have. Take us home...

Thank you so so so much, Mike, for bailing me out yet again! I am eternally grateful to you for taking the time to write this post - it is quite clear that you take a lot of time and effort writing it.

I am not sure why I have not written about this puzzle before - I agree fully with your analysis that this is an absolutely brilliant puzzle and essential for every puzzler's collection. I am truly impressed that you were able to solve this as an assembly puzzle - I could not have managed that but for others thinking of buying a copy, it is just as much fun, if slightly easier, solving this as a disassembly challenge. The stainless steel version is incredible but in the absence of a supplier for these, it is still worthwhile buying in acrylic or, as will be happening very soon, in anodised aluminium - there are just 7 days left on the Kickstarter campaign to get the Dirty Dozen and L(8)tice designs from Jerry and I would heartily recommend getting both (but expect the L(8)tice to be the tougher of the two). The Kickstarter campaign also includes one of Ray Stanton's wonderful coordinate motion designs, the Slideways burr - I have written about 3 of the shape transformations of these made by the New Pelikan Workshop:

Slideways Cube

Slideways ball

Quad Slideways ball

If any of you feel the urge to contribute a guest post to help me maintain my weekly streak of publishing, then please contact me and we can come to some arrangement. In the meantime, I had better solve something quickly for next week!

Enjoy the rest of your weekend - keep puzzling!