Octagon Box

I recently purchased Octagon Box from the last CubicDissection auction. It is a Bits and Pieces reproduction of Pile of Disks by Akio Kamei. I had seen it before on Rob Puzzle Page, where he lists the many Bits and Pieces boxes he has purchased over the years. He said this was one of his favorites, so I was happy to see that Eric was selling it. Jeff also did an entry about this puzzle.

There were a few cosmetic issues, so I got a pretty good deal on it. Two of the joints are separating a bit, and it has a few dings on the top. Still, the mechanism works quite well, so I'm quite happy with it. Photo by Eric Fuller.

Visually, it is a nice looking puzzle. The laminations are quite well done, and it has a nice finish on the exterior. There is a nice bevel running along the top and bottom edges, as well as between the lid and body of the box.

Oddly, one segment of the laminations that is supposed to be dark ended up looking light, which kind of throws things off a bit. I thought that this might be a clue at first, but I think it was a mistake. Still, it is fairly well crafted for a Bits and Pieces box.

It took me about 3 minutes to figure this one out, but I think I got lucky. I took a glimpse of the mechanism, thought that I understood it, and then put it back together. Much to my surprise, it didn't work quite like I thought it did. After another 5 minutes I had it open again, and this time I studied the mechanism a bit more.

The mechanism is pretty clever, there are a few little details that were included that make it a nice puzzle. There are some dead ends that sort of give you a hint as to how it works. The one drawback is that solving it can feel a little random, but that is frequently the case with hidden mechanism puzzles.

Overall, a solid puzzle! I'm glad that I was able to find it for sale.

T4 Popplock

I recently read Jeff Chiou's blog post about some puzzles he borrowed from Jonas Bengtsson, one of which was the T4 Popplock by Ranier Popp. I have seen his awesome looking puzzle locks online, but haven't purchased one yet since they're pretty expensive. Jeff ended up buying a T4 after he borrowed one from Jonas, and he was kind enough to offer to loan it to me. Thanks Jeff!

As you can see from the photo, it as a beautiful looking lock! All of Ranier's locks are individually milled out of brass, and the precision is superb. It is an extremely heavy puzzle, weighing in at over a pound (793g). It comes with a key.

When it arrived, I started working on it right away. As Jeff mentioned, the first move is pretty easy and I discovered it fairly quickly, since it is a standard trick. I also discovered a feature that I knew would be of importance, but was unable to proceed further.

I was stuck at this point for two weeks, playing around with it here and there for a half hour at a time. I emailed Jeff to let him know what I had tried and see if he could offer any small hints help me out. He provided a few bits of information about what not to do, which helped narrow down my search a bit.

This Sunday I headed up to my parents' house and brought a few other puzzles that they could check out, and figured I would bring this one along to see if I could make any progress.

Sure enough, while I was showing it to my mother, something new occurred to me! It was quite a relief to finally be making progress after 2 weeks of being stuck at the same spot. My hopes were high that I was moments away from figuring it out completely, however I immediately became stuck again. I learned slightly more about the feature that I knew would be of importance, but didn't actually discover the next step yet.

The next day, I finally figured out the next step! It was quite similar to what I had already tried, I just wasn't doing it quite right. I think that is my only criticism of this puzzle: this step is a bit harder to discover than it needs to be. There were a few things that could have been done to make it a bit easier to stumble upon, which wouldn't have decreased the difficulty or enjoyment of the puzzle much.

The next and final step only took me a minute or so to figure out, but it is quite cool. I didn't do it quite as intended, but it worked. The intended solution is even more elegant.

In total, I think I spent somewhere between 10 and 15 hours on this one. Puzzles like this take a ton of patience, since they give you so little to work with at first. Many hours of pushing, pulling, twisting, rattling, and whacking trying to figure out what is going on.

Jonas mentions in his blog post that this lock is as good if not better than Danlock (the gold standard for puzzle locks). I think I would agree that the craftsmanship is definitely superior: it is a much more complex mechanism that must have taken a lot of work to produce. As a puzzle, I still think I slightly prefer Danlock.

They both have some neat elements, but Danlock's simplicity gives it a bit of an edge in my mind. I could definitely see how some folks could tilt the other way if they prefer a more novel and clever mechanism. If the second move of the T4 was a bit easier to discover, I think it would have been a bit better.

Overall, an awesome puzzle that I would highly recommend if you have the budget for it. I am tempted, but I probably won't be buying one since they are so expensive and the International Puzzle Party is coming up. Woo hoo! This and other Popplocks can be purchased from Puzzle Master and Grand Illusions.

Thanks again to Jeff for making this review possible!

Twist the Night Away

Back when I was looking for interesting puzzles to build out of my LiveCubes, I stumbled across Twist the Night Away in this thread on the Puzzle World Forums. It is a 4x4x4 cube designed by Tom Jolly that requires 7 rotational moves to disassemble, which is quite remarkable.

Usually I'm not too keen on purchasing puzzles that I can build fairly easily with LiveCubes, but Eric Fuller was selling a wooden version for a very reasonable $40, so I decided to pick one up.

I loved Eric's description of this puzzle:

I was showing various puzzles to an IPP attendee when they skipped right over this one. I started to show it to them and they said "Everything interesting that can be done with 4x4 cubes has already been done". I laughed and showed them about half of the solution, at which time they cried "Stop - I'll take it!". This really is a fabulously interesting cube, and Tom really hit the ball out of the park with it. It's just a downright fun puzzle that still puts a smile on my face to solve.

Indeed, this really captures it perfectly: it is a remarkable design! In addition, Eric did an excellent job crafting it. The pieces fit together perfectly, and have a nice finish on them. It is made out of Carolina Mountain Ash and is 3 inches square. I really liked the way he constructed the pieces: it gives the puzzle a nice appearance on the outside when it is assembled.

Even though I had solved this one before with LiveCubes, it was a much better experience using actual wood since I didn't have to worry about the pieces coming apart. Not only is this a non-trivial puzzle to disassemble, I would say it is actually pretty tricky.

The first three pieces come out quite easily, but the remaining two pieces are trapped by a 4x4 'hoop' structure. Even knowing the solution, it still takes me a few minutes to remember how to do it. Also, check out Jonas's blog post on this one.

Putting it back together is even trickier. I brought it to a family event a few days ago and somebody was able to get it apart, but it took me about 15 minutes to get it back together again.

If you have a set of LiveCubes, head over to Puzzles Will Be Played to see what the pieces look like and give it a try. You won't be disappointed!

Oskar's Matchboxes

Oskar's Matchboxes is an interesting puzzle designed by Oskar van Deventer. It can actually be constructed by just gluing together matchboxes that are of the standard 3:2:1 proportions. I wasn't planning on buying this because I figured I could always make them out of matchboxes, but I never got around to it. Recently I decided to pick up a copy at The Games People Play in Harvard Square.

The version I got was made by Philos Games, a German company that produces as wide assortment of puzzles and games. Since it is mass produced, the price wasn't too bad at around $25. It has a nice appearance and even though the wood is unfinished, it has been sanded smooth. It is made out of Cassia Siamea and Beech, for a nice contrast. The Cassia Siamea has a nice grain pattern. The fit is a bit loose, but passable.

The puzzle itself consists of five pieces, each of which is made of a drawer attached to a lid. (In this version, the 'drawers' are actually blocks of wood.) The objective is to get all of the five matchboxes closed.

When I first tried this one, I got really lucky and was able to solve it in under 5 minutes. Pretty much the first thing I tried worked, which was quite surprising. I shrugged and figured it was an easy puzzle. A few days later I decided that I should probably try it again before I write my blog post, and sure enough it took me quite a bit longer, maybe 20 minutes or so. I must have just randomly positioned the first two pieces correctly on my first attempt or something.

During my second attempt, I discovered a second solution because I was attempting to solve it in a more systematic fashion. I prefer the appearance of the first solution I found to the second: the first one has boxes jutting out in all directions, while the second solution has one side that is flat.

I'd give this a 6/10 in terms of difficulty. It does take a fair amount of patience, but I think most folks will be able to get it if they keep at it for a little while. Overall, this is a solid puzzle, I'm quite pleased with it.

Trevor Wood, Tom Lensch, and Eric Fuller have each made runs of this design, and each one looks a bit different since the thickness of the wood can be chosen by the designer. Here's a photo of the version made by Tom out of super-thin 1/16" wood to replicate the look of real matchboxes. Very cool!

Interestingly, on Trevor Wood's site, he mentions that there are three possible solutions, but Eric and Tom both say that there are two. Trevor says that the third is only possible if the size and position of everything is just right. I haven't found a third solution on mine yet, but I'll keep at it!

Cast Square and Bamboo Soma

Yesterday I stopped by Eureka to pick up a new puzzle by Hanayama, Cast Square designed by Vesa Timonen of Finland. I was eager to give it a try, since they haven't come out with a new difficult puzzle in this series in a while. This one was rated 6 out of 6, so I was hoping that it would be a good challenge.

It has a great weight to it and I really like the appearance. The contrast between the gold and silver is nice; I like it when they use a shiny finish like this.

The motion of the puzzle is also quite nice: the pieces slide apart in an interesting 4-piece coordinate motion. However, they stop short of coming completely apart, so the puzzle is to get them apart and back together.

I tried a number of things, but couldn't get beyond just sliding the pieces apart and together. After about 5-10 minutes, I discovered something that helped me figure out how to get it apart.

Unfortunately, it turned out that this puzzle was vulnerable to my "shake-the-hell-out-of-it" approach. I don't really consider that a spoiler, because that is not the correct solution. So if you want to get the maximum difficulty of this puzzle, don't just try to pull it apart while shaking it. After inspecting the pieces, I was able to see what the correct solution was, so I'm not sure how much longer it would take to figure it out the proper way to do it.

Interestingly, depending on how you reassemble it, the solution is different, which is quite an interesting feature. However, once you have disassembled it once and seen how it works, finding the additional solutions is only moderately challenging.

Overall, a decent puzzle, but you can solve it by doing one of the first things frustrated people do: just shake it around randomly until it comes apart. It would be much more interesting if it was designed in a way that makes this not work, which would also make it much more difficult.

As I mentioned in a previous post, I found a series of bamboo puzzles produced under the name "EcoGame" at Urban Outfitters. In the comments, Roland Koch noted that in the photo I posted of the full lineup, the Soma cube looked quite similar to his 2002 IPP Design Competition entry, Soma Summarum, but with a slightly different objective.

In Soma Summarum, the objective is to create the pattern shown here. An interesting variation on the classic Soma.

In the bamboo version, this was obviously impossible, but Roland thought that perhaps the objective had been changed to make the layers appear all the way around the puzzle.

I was curious if this was indeed the case, so decided to pick this puzzle up while I was at Eureka as well.

As soon as I got it out of the packaging and looked at the pieces, I thought it was pretty clear that this objective would not be possible. I fiddled with it for a few minutes to confirm my suspicion, and tried it out in BurrTools just to be safe. Oh well!

It looks like the striped pattern is more just for esthetics than as part of the puzzle. Here is the full set of pieces:

Still, it is actually a fairly nice Soma cube: the finish is pretty good, the striped pattern is interesting, and the pieces fit together very well. I'll probably find one of the many websites that has shapes that you can make from these pieces and have a grand ol' puzzling time with them.

Alcatraz Revisited

As I was heading out of my apartment on Sunday to go to a picnic, I happened to glance at a package by the front door of the building. I wasn't expecting anything, but you never know! And much to my surprise, it was addressed to me. I opened it up, and discovered a copy of Alcatraz! It turns out, Brett Kuehner read my blog entry about failing to solve it at the Museum of Science, and sent be a copy as a birthday present! Thanks Brett!

When I got to the subway stop, I opened up the package and tried to solve it again. I felt like I was on the right track before, so I tried a few of the things I had tried before. However, since it was mine, I tried using a bit more force than before, and that ended up working! (Note: By force, I don't mean just pushing the ball through the bars, that would surely damage the puzzle.)

I brought it to the picnic and stumped a few folks with it. One knew the solution already, but he knew not to give it away. Another figured it out after a little while with some hints. I found that often people tried the right action, but they just didn't do it quite right.

You can read more about this puzzle and how it was invented on the designer's website: AlcatrazThePuzzle.com. It was designed by Brian McDermott, a magician, as part of his act. After he magically removed the ball from the cage, he would pass it around to the audience to inspect. It proved so popular that he decided to sell it as a puzzle. According to his website, over 700,000 copies have been sold! At $13 each that's not too shabby!

It has a nice solid construction with black molded plastic cage, solid brass bars, and a solid steel ball. The steel ball gives it a nice weight. It has a simple appearance but also looks impossible to the untrained eye, which I think may be part of the reason for its success.

My one complaint about this puzzle would be the amount of force required. However, if it was modified to require less force it would be quite a bit easier, which probably isn't desirable. I'll bet the reason this one is so popular is because it has the ability to stump folks for a very long time!

Overall, a neat puzzle, but not something I would subject my non-puzzling friends to again, since it is quite difficult. Puzzlers, on the other hand, have probably seen this mechanism in other applications if they enjoy this type of puzzle. Check out Oli's review of Alcatraz here.

Thanks again to Brett for the puzzle!

Wausau '82

As I mentioned in my post a few weeks ago, when I last visited Eureka I was eyeing a copy of Bill Cutler's Wausau '82. This last Sunday when I was going out to dinner with my parents for my birthday (my birthday is actually today), my they surprised me with it for my birthday present! Thanks Mom and Dad!

As I mentioned before, I had been eyeing this puzzle at auction way back in February of 2009. Bill Cutler says on his website that it was one of his favorite designs (and Bill knows burrs!), so I knew this was going to be a good one. I was quite curious to see what the "lock-picking technique" he described involved.

It was made by Jerry McFarland, so the craftsmanship is superb. The fit is perfect, not too tight or too loose. It has a nice smooth finish and is crafted out of cherry, walnut, and maple.

When I got home, I started working on it right away. Like when I first tried it at Eureka, I got stuck in a cycle of dead-ends and couldn't figure out how to proceed for about 10 minutes. Eventually, I discovered the technique that Bill mentioned. I was a bit surprised that I hadn't noticed it before, since it is similar to techniques I have seen in other puzzles. However, Jerry has implemented an additional mechanism that ensures that you can't stumble upon the solution accidentally.

The tricky part is getting out the first piece, after that, the rest of it comes apart quite easily. At first, I started to keep track of where the pieces came from, but I decided not to be a sissy and scrambled the pieces. I figured it wouldn't be too hard, since the different axes are different colors.

It definitely wasn't easy, but it was doable. I think I got it back together in about 15 minutes. It took me a while to figure out what went where, but the organization is fairly logical. Some of the pieces are identical, which makes the task somewhat easier as well. It was a bit tricky figuring out what order I had to put the pieces in, since they tend to get in each other's way.

Overall I really liked this puzzle. The disassembly was clever: the unobservant puzzler could end up going in circles for a while. I also really liked that this one wasn't a complete nightmare to put back together: I don't like to have to keep track of how it comes apart or risk spending weeks trying to reassemble it (or using BurrTools). Thanks to my parents!

Puzzles at the Museum of Science

A few months ago, when visiting the Museum of Science in Boston on a Saturday, I encountered an area of the museum where folks were playing with mechanical puzzles. Needless to say, I was delighted and stuck around until the museum closed. Last weekend, I made another visit and did a better job of documenting it!

The puzzle exhibit has been run by a volunteer named Barry Kort for over 20 years! Every Saturday he brings in an assortment of puzzles from his collection and sets them out on a bar with stools for folks to play with. This picture is from 10 years ago so things look a bit different, I didn't think to take my own.

Barry brings sturdy puzzles that can take the abuse of thousands of folks beating upon them. He has a variety of different types from assembly, to disassembly, interlocking, hidden mechanism, and disentanglement.

The first one that struck my interest was this metal disassembly puzzle. I'm not sure of the name of it, but I'm guessing it was something from Bits and Pieces a long time ago. [UPDATE: This is Prison Block from Bits and Pieces.]

It consists of a rectangular black piece with a rotating purple knob on the top. The black piece is seemingly too large to fit through the hole in the silver base. The puzzle is to remove it.

I was quickly drawn to this one because it looked so simple: it made me curious what the solution could be. It took me about 15 minutes to figure it out. I would say that it is easy/moderately difficult to puzzlers, but might prove pretty tricky for a non-puzzler. The solution is based on a common principle in hidden mechanism puzzles.

The next one I tried out was Arrow Case (a.k.a. Packing Arrows) from Bits and Pieces. It is a design by the prolific designer of tray packing puzzles, Dai Nagata. This design won a first place award in the 2001 Puzzle Design Competition at IPP21.

The construction and finish is quite nice, though this copy was quite worn. The pieces had a nice weight to them.

I thought this one was going to take me a while, since frequently the solution to these types of puzzles is quite un-intuitive. However, this one was pretty logical. I think it took me about 5 minutes to  figure it out. Overall, a nice little puzzle!

Barry had a few of this type of puzzle: I tried Houses and Factories next. It is a design by Dick Hess that was also produced by Bits and Pieces.

In this one, they give you a little spot to store the last piece, which I liked. Similar to Packing Arrows, the pieces had a nice weight and finish to them.

Of course, the idea is to get all of the pieces into the square frame on the left of the tray. There are two identical houses and three factories. Two of the factories have a smokestack on the right, and one has it on the left.

It would be quite easy without the chimneys and smokestacks: they have a tendency to get in the way. At one point, I found a solution that required flipping one of the pieces, but that was illegal because the pieces are only decorated on one side. After a few more minutes of fiddling, I figured it out. This one took me about 10 minutes, a bit longer than the other one. It is a nice little puzzle!

Next up, I took a crack at Oskar's Blocks, a design by Oskar van Deventer. Somebody had taken it apart and wasn't able to get it back together, so I decided to take a crack at it since disassembly is pretty trivial.

It has a nice kind of pinwheel shape when you get it together. It took me about a minute to get back together, but that's probably due to my experience with this type of puzzle. It is a nice little design, though a bit simple for my taste.

A woman had been working on Free the Key for a while and was able to get the disk off, but didn't have the patience to get it back to the beginning, so I decided to give it a try.

This one took a bit of fiddling, but eventually I got it back to the start after a few minutes. For the sake of completeness I took it off and put it back on again.

Like many other puzzles, you can think of this as a maze. The key is to have a good awareness of what you have tried so you can avoid going in circles or repeatedly running into the same dead end.

Overall, a sturdy little puzzle, but I didn't much care for the finish. It was a bit dull, I would have liked a nice shiny finish for this one, but that's not a big deal. I've seen them new, and they look similar so it wasn't due to wear.

Next up, I tried Satan's Stirrup, the very first original design produced in 1985 by Tucker-Jones House, makers of The Tavern Puzzle® Collection.

This one is a level 4 out of 8, so not too tricky. I think it only took me a minute or so to solve. Not too hard, but it might keep a non-puzzler occupied for a little while. Still, a nice puzzle that will definitely hold up to some abuse.

The one puzzle that completely stumped me during this visit was the classic Alcatraz Puzzle. Believe it or not I don't own it and I have never solved this puzzle, which is quite surprising since hidden mechanism puzzles are one of my favorite types.

I worked on this one for a good 20 minutes, but didn't have much luck. I whacked it, spun it, and shook the hell out of it, but nothing seemed to quite do the trick. I'm thinking I had the right idea, but didn't quite get the technique correct. Oh well, I'll have to revisit this one another day!

One of the coolest things about this exhibit is getting to watch everybody else working on their puzzles. I'm always curious to see how different people approach problems, how much frustration they'll tolerate, and who can figure out what. It seems to really come down to confidence: if folks go into it thinking that they'll fail, the usually won't! Puzzle solving takes the confidence to know that if you keep at it for long enough, eventually you will succeed.

As the museum was about to close in 10 minutes and Barry was starting to pack up things that folks weren't working on, I noticed that Internal Combustion was disassembled and decided to try to put it back together. This type of puzzle is called a framed burr: there are four notched rods that go through the outer frame.

I had done this one before: it is moderately tricky to get it apart, so I kept all the pieces in the correct orientation for easy re-assembly. In this case, the pieces were all scrambled.

Using some logic and trial and error, I was able to figure out the correct locations and orientations for the pieces. Just as they were making the final announcement that folks needed to head out, I slid the last piece into place. Phew! That was pretty exciting! I hate leaving a puzzle unsolved.

Next time, per Barry's request, I'll bring some of the more durable puzzles from my collection. I find it quite unfortunate that a lot of them just sit around unused once I've solved them, so I'd love the chance to see other people enjoy them. Thanks to Barry for a thoroughly enjoyable afternoon!

Mirrorkal Escher and Digits in a Box

I stopped by Eureka recently and checked out some of the new puzzles they just got in. David Leschinsky, the owner of the store, was there, which was nice because he pointed out all the interesting new puzzles they got. I was particularly excited to see some of the new Vinco puzzles.

His 2010 collection has quite a different appearance from his usual puzzles: they are quite nicely finished and some have interesting, rounded shapes. The rounded tetrahedrons look particularly cool. David had a Tetrahedron that had been disassembled, so I got to try putting it back together. It is a four piece coordinate motion puzzle, and I didn't find it too difficult.

I was also quite curious to try out Dual Tetra-hedron, which has quite an interesting appearance. It is also a four piece coordinate motion puzzle. This one was already assembled, so the challenge was to figure out how to get it apart.

After a bit of wiggling, I figured out how to do it, though I didn't disassemble it fully. I didn't study it, but I'm guessing that the mechanism of Tetrahedron and Dual Tetrahedron is quite similar.

I thought about purchasing one, since they are quite cool looking, but they were a bit rich for my blood ($95 and $135 respectively).I liked them, but not quite that much!

Another cool puzzle that I saw was Wausau '82 by Bill Cutler and made by Jerry McFarland. I had eyed this puzzle before on an online auction. I had read that this burr was one of Bill's favorite designs and involved a lock-picking technique. Since I used to pick locks, that sounded pretty interesting and I had been wanting to give this puzzle a try.

I played around with it a bit, but kept going in circles. It is just as well, since I'm sure that it would take a while to put it back together as well! I'd definitely consider getting this one at some point, but didn't end up going for it on this visit. It looks like the one copy at Eureka has sold now, but I think you can still buy them directly from Bill.

Well, enough about the puzzles I didn't end up buying: I did end up buying two. One that caught my eye was a puzzle called Mirrorkal Escher designed by Ivan Moscovich. There are nine cubes, each of which contains a mirror. Two adjacent faces of the cube are clear, and the other four faces have part of an image on them. The frame that holds the cubes also has parts of the images along the outside.

The objective is to arrange the cubes in such a way so that one of five possible Escher prints can be seen. Pretty cool idea, eh? I like Escher, so this was a winner with me. I fiddled with it a bit at the store, enough to tell that it wasn't entirely trivial, so I decided to buy it.

It is an interesting puzzle to solve, you need to use logic to figure out how to position the cubes. It isn't as easy as it sounds, because there are seemingly multiple correct positions for individual cubes. For example, the center piece of the image can be reflected from the edge of the cube to the north, south, east and west of it. However, if you go down the wrong path, you'll end up unable to complete the image with the remaining pieces.

It took me about 15-20 minutes to solve the first one, and each subsequent one took a bit less time as I started to get the hang of it. For $20, I got a good amount of enjoyment out of it. It isn't too difficult to give to non-puzzling folks, which is nice too. My girlfriend enjoyed it as well, and she doesn't typically have the patience for puzzles.

One thing that bugged me about it is the fact that the cubes appear to scratch fairly easily. The display model at Eureka was pretty scratched up, and I noticed that mine started to get scratched a bit as soon as I started fiddling with it. Oh well! At least it is cheap.

The second puzzle I got was another one I had seen online before, Digits in a Box by Eric Harsh-barger. It was his entry in the 2007 Puzzle Design Competition at the International Puzzle Party. The idea is to fit the digits 0-9 in a 5x5x5 unit box.

I really liked the appearance of this puzzle: the box is clear plastic, and the pieces are made out different colored acrylic that has (presumably) been laser cut. The colors chosen are quite nice: blue, pink, lime green, orange, ruby red, purple, teal, gray, white, and brown.

The original competition entry was made out of machined aluminum for the pieces and wood for the box and cost $200. The plastic version is only $15, now that is more my style!

As a puzzle, it is quite tricky: there are quite a few pieces that are dissimilar, which makes it fairly challenging. It took me quite a while to figure it out, but eventually I got it. Using BurrTools, I found that there are 4239 solutions. Many of them are just slight variations on the same idea, but there are still a lot of different solutions.

I have a really hard time figuring out additional solutions once I already know one. Once I know a solution, it feels like the pieces have to go that specific way. I'll have to spend more time working on this one and see if I can figure more out!

Overall, this is a great puzzle! You can get the plastic version from Eureka or from QuickBrownFoxPuzzles.com, who appears to be producing them. I think the only downside is the difficulty, but there is definitely plenty of re-playability, particularly if you have a bad memory! Initially it seems impossible, but as you play around with the pieces you start to understand how they interact and can fit together.

Double Escape and Crazy Elephant Dance

When I was down at NYPP, Brett Kuehner was kind enough to give me Double Escape, which was Markus Götz's IPP26 exchange gift. It is a disentanglement puzzle, and Brett isn't a big fan of disentanglement puzzles, so he thought I might enjoy it. Thanks Brett!

Most of the disentanglement puzzles I have are of the 'all rigid' variety, such as these Dick Hess wire puzzles. The ones with a flexible component like rope can be pretty tricky and it is sometimes easy to get them all tangled up, so I have shied away from them somewhat. However, I really enjoyed Dinghy and Holey Bolt.

Double Escape is a cool idea: there are two objectives of varying difficulty. The dark ring on the right hand side is "easy" to remove (according to Markus), but the one on the left is more difficult because you are restricted by the length of the rope. It is an extension of his earlier design, Narrow Escape.

Since I'm not too familiar with this type of puzzle, even removing the easy ring took me about 30 minutes or so. Now that I know how to do it, it seems pretty easy, but at the time I remember being pretty puzzled.

Removing the second ring baffled me for quite a while. I left it on my end table and worked on it on and off for a few weeks. Usually I didn't spend much more than 10-15 minutes on it, so I think the total time is somewhere around 2-3 hours.

Since I tend to be better at solving puzzles in the morning, I decided to give it a shot this morning when my mind was fresh. Typically, I was only working on it after work, and work was pretty busy so I think my mind was a bit weary. Sure enough, after about 30 minutes I had figured it out!

The solution is quite cool: you really need to think about your strategy for removing the first ring and see how you can apply it to the second ring. Simply doing the same type of moves doesn't work, because of the length of the ropes, so you need to be a bit creative to find the space to remove it.

Markus rated it a 5-6 on a 1-10 scale in terms of difficulty, but I found it a bit harder than that. It really depends on your experience with a particular type of puzzle, I think. Overall, a great puzzle: it is a very nicely crafted puzzle with a nice finish. It is also fairly large and quite sturdy.

When browsing Markus's website, I noticed that he was also the designer of Crazy Elephant Dance, which is a trinary version of one of the puzzles that started my interest in puzzles, the Chinese Rings/Patience puzzle. Crazy Elephant Dance won an honorable mention in the 2005 Puzzle Design Competition at IPP25.

Its mechanism is similar to Spin Out (which is Chinese Rings with a different mechanism), but rather than having two positions for each disk (binary), there are three positions (trinary). This means that rather than doubling the number of moves with each additional disk, the number of moves triples! Well, the actual formula is more complicated than that, but it is close. In addition, unlike Spin Out, you can make wrong moves that leads to a dead end, so it is a bit tricker!

I had always wanted to give this puzzle a try, and Markus actually has a Java applet on his website that lets you try his puzzle online! It was a lot of fun, since the applet allows you to see how the mechanism actually works when you click the mechanism button. Definitely check it out if you haven't had a chance to try it before and enjoyed Chinese Rings.