Pieces of Eight

One of the things I really appreciate about a lot of Stuart Coffin’s designs is that they start from an interesting point of departure, then develop a few themes before settling on a particular puzzle design – if you read his book Geometric Puzzle Design you’ll find a lot of examples where he’ll start with a particular set of pieces, restrict them somehow and then use the resulting items to develop a puzzle.

I think Pieces of Eight is one of Stewart Coffin’s classic puzzle designs and it starts from a beautifully simple premise that Coffin develops in chapter 22 "Theme and Variations", and then turns into a wonderful little puzzle.

Pieces of Eight starts with a simple dissection of a cube into two identical C-shaped pieces. Two of those C-shaped pieces can then be joined together in eight possible configurations that will allow the cubes to be completed by joining on another C-shape – omitting rotations or reflections. That’s interesting - but then Coffin notes that those eight pieces can then be assembled into a 2*2*2 cube – that’s a puzzle! In fact he poses a number of assembly challenges for the reader using those pieces including a 2*2*1, 2*3*1 and some step formations.

My copy came from a recent auction that saw Eric Fuller reducing his stash of his own puzzles a bit – so I was able to purchase an unusual copy of this puzzle with the pieces made in Bocote. The assembled pieces fit neatly inside a cherry box signed and dated on the base by Eric. Tipping the pieces out leaves a 2*2*2 cube on the desk – the fit on the pieces is rather good so the cube holds together very nicely – and the finish is so darn good that when it’s assembled, it’s pretty darn hard to find any visual clues as to where the pieces separate – so the only way to attack it is to feel your way around the edges, tugging gently in different directions until you find a bit that can be released. Disassembly is reasonably trivial once you identify your first bit to tug free, and the resulting bits are interesting to look at as they’re all different (you were paying attention at the beginning of this post, weren’t you!).

Assembly on the other hand is anything but trivial! I can vouch for the fact hat there are stacks of ways of snookering yourself right at the death – everything goes together brilliantly only to leave you with a piece that will only fit at right angles to the rest of the cube, or worse still, leaves you with a set of misaligned holes.

Pieces of Eight has been around for ages – and I think it’s rightly earned its place as one of the classics – and I rather like my copy from Eric’s collection…

Tern Key

Open

I got my hopes up when I spotted a copy of Tern Key up on a puzzle auction recently – and suspect I got lucky when the folks with the seriously deep pockets appeared to be way more interested in some more exotic items, leaving me to buy it at a fairly reasonable price.

I’d spotted Tern Key among the gallery of past offerings on Cubic Dissection and thought it looked rather nice. Designed by Goh Pit Khiam, this puzzle shares the same underlying principles as his Ternary Burr – both of which extend on the basics behind the Chinese Rings. While the Chinese Rings (and indeed Pit’s earlier Key Puzzle) is a binary sequence, Tern Key (and Ternary Burr – must try and find one of those at a reasonable price one day…) is based on a ternary, or base 3, sequence.

Closed

The puzzle is effectively a series of latches that must be released in sequence, but each latch forces you to effectively undo most of what you’ve already done – and there are three steps to releasing each latch in the case of the Tern Key.

Eric Fuller made 50 copies of Tern Key back in 2009. They’re manufactured using acrylic, nylon and stainless steel – so they’re really shiny and won’t ever get tired-looking. It is really nicely made and not only looks great, but the movements are all neat and crisp and positive as well – all 134 moves of them in the full solution. With all the clear acrylic, you can see exactly what you’re trying to do all the way through solving the puzzle – which finally sees the key piece being completed released and removed. Eric’s taken a lot of trouble to make sure that the bits of stainless steel used as pins and posts are all neatly polished and look terrific.

 

Puzzle-guru Dr Goetz Schwandtner has written a great paper on this class of puzzles, concentrating on Kugellager, which is a quinary (base 5) extension of the principle. The paper is available for download over here and you’ll find mention of all of the variants discussed in their appropriate sections in the paper. One of the eye-opening bits of the analysis is a graph showing how the complexity of the solution explodes super-exponentially as the number of latches (or rings) increases.

L-Bert Hall

Ronald Kint-Bruynseels entered this puzzle in the IPP 27 Design Competition under the full title “(Now they know how many holes it takes to fill) The L-Bert Hall” in a great take on the line from the Beatles classic “A day in the life”. The puzzles were made by Eric Fuller who subsequently offered 30 copies for sale on Cubic Dissection in October 2007. Eric’s description at the time mentioned that he was quite proud of the results and made specific reference to the box tolerances being “close for a nice fit”.

My walnut and quilted maple copy came from a recent Cubic Dissection Auction and I was very chuffed when I managed to secure it with a reasonable bid.

Four years on, there’s still a lot of evidence of those close tolerances – half of the pieces refused to exit box when it arrived in Blighty, despite my ‘encouragement’ of the agricultural variety! A few days on the windowsill in the full, mighty glare of the English sun (40W equivalent for those of you not familiar with this particular phenomenon) had loosened the pieces sufficiently to allow a more elegant exit.

Ostensibly this is a really simple little puzzle made up of nine identical pieces: three blocks in an L-shape with a perpendicular dowel protruding from one block and holes drilled through the other two blocks. The aim is to build a 3*3*3 cube to fit in the (rather snug) box (so clearly the dowels can’t face outwards, but I like your thinking!).

Intuitively it feels like it should be a fairly simple puzzle, and indeed, if those jolly dowels weren’t there it would be! Burr Tools confirms that if the dowels weren’t there, there would be 111 ways of arranging those pieces into a cube, however, the introduction of those dowels makes the solution unique(!).

I haven’t managed to come up with a clever way of deducing what the answer must look like (any suggestions from anyone “out there”?), so I’ve been reduced to a form of brute-force attack – but thankfully there are only 9 pieces, and they’re identical, so you can crank through alternatives fairly efficiently…

…a couple of weeks on and the fit is still extremely snug, so I’m airing the pieces on the windowsill for a while longer – with the fierce English sun burning down on them I’m sure that when winter arrives and the central heating really kicks in they’ll be back to designer specifications.

Triple Locked Box

My journey to getting one of Eric Fuller’s Triple Locked Boxes is a little unusual – at least for me. I’d seen the puzzle listed in the gallery over at Cubic Dissection while I was randomly surfing around looking at pictures of nice puzzles (and there are some very nice puzzles in that gallery!). In spite of Eric’s description (his opening line is: “Although it looks relatively modest on the outside, this is a phenomenally difficult puzzle box to open.”) I hadn’t really paid a huge amount of attention to it. I’d seen one or two of them on the usual auctions and hadn’t really lusted after it much.

Earlier this year there was a short conversation on the Renegades Forum where someone was asking about a video that Eric had produced demonstrating the mechanism – and a link to the video was duly produced. Being the inquisitive sort, I had a look at the video – it’s fair to say that it blew my little mind, rather comprehen- sively. Any video of a puzzle solution that starts halfway through the solution with the opening remark that “I’ll start from this position because most people have been able to get this far” deserves attention! I love the unspoken implication in there that most people haven’t been able to get past this point – and then seeing Eric demonstrating what comes next makes it pretty clear why not many people had made it past that point – it also made me want to add one of them to my little collection, rather seriously!

One came up on the latest round of Cubic Dissection auctions and I managed to acquire it … as a puzzle box it is fairly modest-looking, possibly even nondescript, if that’s a fair description of a beautifully finished albeit reasonably featureless box. Eric made “approx 34” (which struck me as an interestingly specific generalisation) in a variety of different woods – some of them had different woods on the outside, this one was finished entirely in quilted maple – a lovely, interesting-looking wood and the innards are made from padauk.

Being four and a half years old now, the first move pretty much does itself – in the process establishing it’s credentials as a Japanese-style sliding panel box, and indeed the next five or six moves reinforce that assumption perfectly and result in the top of the box being partially open … and this is the state where Eric’s video starts …

At this point there’s a compartment inside the box available to you that has a revolving false floor that appears to be hiding a little aluminium and steel tool. The false floor is clearly revolving on a pair of pins and seems to serve purely to hide (albeit not that successfully!) this little aluminium tool. The false floor is pretty obvious since it’s at half depth in the box, but doesn’t give you much of a suggestion on how to progress…

There isn’t anything obvious worth trying with the tool you’ve discovered and you might even be tempted into thinking that you’ve finished (because you can’t find anything else to do – perhaps the tool was what you were really after) although there’s clearly still a lot of box you haven’t got into yet … and if I’m honest, if I hadn’t seen Eric’s clip of what comes next, I’d have spent a long time staring at this state.

At this point the only way to work toward the solution would be to start exploring out-the-box suggestions.  Eric’s description includes the line: “this box would not have been possible without my recent metalwork experience” and up to now, none of the mechanics have really relied on much metalwork, and indeed waving a compass around the box confirms that somethings trying to realign the Earth’s magnetic fields – yet finding an accessible magnet is quite a mission – there is one, but it’s so beautifully hidden that I wouldn’t be surprised if most folks never find it without a bit of a nudge – Eric deserves a medal for that aspect alone, IMHO.

Having freed that tool, you still have three things to do, in order, and be warned: they’re as well hidden as the last step! There’s a really satisfying feeling as you do each in order and sense the progress you’re making until the lid is finally able to slide all the way off … now you’re done!

Certainly not the most beautiful puzzle box I have – but definitely one of the toughest! I’m very chuffed to have been able to add this one to my humble collection.

Stickman Snowball

I recently managed to acquire a Stickman Snowball Puzzlebox. (Yeah, yeah – that same Cubic Dissection Auction I’ve been yabbering on about...) The Snowball is based on its smaller cousin, Snowflake, which was Robert Yarger’s 2006 IPP Design Competition entry. Whereas Snowflake was made in holly and just over 1.5” cubed, Snowballs are considerably larger(!) at 3” cubed and come in holly or walnut.  Some Snowflakes were initially given away as gifts with ribbons attached so that they could be used as puzzling Christmas tree ornaments and a bunch were sold through Cubic Dissection back in 2005.

Snowballs appeared in 2009 and seem to have been made in a smaller run – and given the added size and weight, I suspect that nobody has used these as tree ornaments! [...and none of them came with a loop of ribbon attached to them.]

From a distance, an unsolved Snowball looks like a fairly plain box with six unadorned slab sides – close up, the detail in the corners is pretty mind-blowing: when all the panels are closed properly, each corner appears to have three sets of interlocking orthogonal rails – and your brain will instantly tell you that if seeing is believing, and each corner looks like that (they do...) then opening this box is impossible ... great start!

A bit of experimentation will get one of the panels moving – allowing closer inspection of those tricked-out corners ... very neatly done Master YodaYarger! Having slid one panel across releases the next panel, however, to my mind at least, the next move has a panel going “the wrong way” – my mind tells me that a panel with that shape and those cuts should not move in that direction, it should move in the other direction ... and so it continues! 

A bit of backwardsing and forwardsing and after seven moves, the ‘lid’ can be slid off ... and from there you can slide out each of the remaining panels as well, giving you a neat stack of six panels. 

At this stage it’s worth talking about those panels – a couple of them have sticks glued to them to limit certain movements, but on the whole, these are “simply” planks that have been cut in precisely the right place to create a set of interlocking rails and sliders and that astonishing corner detail. The efficiency of it is simply staggering – and I really get why Robert reckons that Snowflake was the closest he’s come to his idea of a perfect puzzle box: nothing is wasted in there ... very clever design Robert!

Triplets

I managed to pick up a couple of relatively modest unusual puzzles on the latest round of Cubic Dissection auctions. One of them was a very plain looking puzzle designed by Jim Gooch called Triplets. This particular one was made in Zebra Wood by Puzzlecraft. 

Perhaps I’m being a bit unfair by calling it plain-looking – but it looks like a simple common-or-garden three piece burr. However, there’s a clue in the name to the fact that this one’s a little different, and a quick glance over at Puzzles will be played – confirms that this puzzle consists of three identical pieces with a rather unconventional shape. 

The oddly shaped pieces are totally disguised when the puzzle is assembled, leaving an unwary puzzler spending half their time pulling or pushing pieces against themselves – evil grin ...

In terms of burr- complexity, this one is about as simple as they get – two moves to remove the first piece and there are only three pieces anyway – but the shape of the pieces will throw anyone who hasn’t seen one of these before off the scent for quite a while ... really cute little puzzle for amusing folks who think they’ve seen one of these before... 

Gesicht

Gesicht (or Face, if you’re Anglish) looks a bit like a stylised face – there are two holes for eyes, beneath which is a mouth with a tongue sticking out and then a series of slots and holes outlining most of he way from one eye around the sides to the other eye…there’s a ball bearing inside the puzzle and a little rod with different sized balls on each end. The ‘maze’ is a pretty simple, straight route, with the only complicating factor being a couple of plastic speed bumps inside the ‘maze’ that mean the ball needs to be encouraged past the bump with the aid of the little rod….so far so good – there are a couple of spots where you need to think a bit about which way up you need to get you rod so that you can do what you want and still be able to retrieve it again, again, so far, so good.

A bit of searching around the inter-web confirms suspicions that the object would appear to be to get the ball from one eye, around to the other and then back again.

All well and good, until you get to one particular final little part of the journey, where you brain tells you that it’s impossible (hook!), so you try getting creative (line!) and then realise that it won’t work (and sinker!).

Several hours later I found myself thinking about it when I had my “You SOD!” moment – fiddled around a bit and confirmed that my solution worked – it’s cute, really cute – it’ll make you smile and probably even make you respond to that little face in kind…