April 21, 2011

Get a Clue!

Get a Clue! is an interesting puzzle by Pavel Curtis that I picked up at IPP30 in Osaka. It was Pavel's exchange puzzle it Osaka, and when I heard his description of it, it sounded like a fun little puzzle that I should check out. He didn't have many left over after the exchange, but I managed to pick one up.

I forget the whole schpiel, but the premise is that there has been an attempted murder, and your goal is to figure out what happened by reassembling the broken magnifying glass in two different ways. The instructions say that the goal is to find the clues to a famous fictional attempted murder.

The interesting thing about this puzzle is that there are nine pieces that must be arranged in three levels to form an image, using the transparency/opaqueness of the different pieces. Not only that, but there are two different ways to do this, each producing a different image!

I figured out pretty quickly what the attempted murder was based on various cues, but actually assembling the puzzle proved fairly challenging. I think it took me a good 20-30 minutes to get both images solved. I found one to be easier than the other, which was clearly by design. At first, it is a bit unclear how you can take a logical/methodical approach to solving this one, but it turns out that there is indeed a way to do so once you make the first leap yourself.

I had this one sitting on my coffee table, and folks would invariably be draw to it, only to accidentally dump out the pieces! Usually I would steer them away from it, since it is a bit challenging for a dinner party of non-puzzlers, but two folks were really intrigued when I explained the goal to them. The proceeded to spend what must have been 45 or 60 minutes trying to piece it together. Finally, they figured out the first image, but had to return home before getting the second one. Like me, they were able to figure out the murder victim before actually assembling either image.

Since the exchange, Pavel has revised the puzzle a bit to actually tell you who the victim of the murder was, and that you need to find two things that they were given. I think this makes it just a bit easier, so if you end up purchasing this puzzle and you'd like more of a challenge, don't look too closely at the text on the handle in the image above and maybe cover it with masking tape when you get the puzzle so you don't peek at it. Like I said, you'll probably figure it out who the victim is pretty quickly, so this doesn't matter much.

I can't really think of any drawbacks to this one. Maybe it would have been nice if the victim is revealed only after you figure out one or both images, but in that case, it would have been really hard to figure out what image you're trying to make. I think Pavel made the right choice there.

Overall, a fun little puzzle that I enjoyed solving. I really liked the multiple solutions, since it increased the amount of puzzling enjoyment and was clearly more difficult to design than just a single solution. The laser cut acrylic construction is nice too!

If you are interested, Get a Clue! can be purchased at PavelsPuzzles.com. While you're at it, check out Octamaze too. It is an interesting multi-layered puzzle by Pavel that I wrote about here.

April 19, 2011

Cast W-U

Cast W-U is a variation on Cast Horse (blog entry) by Nob Yoshigahara. Puzzle Master was kind enough to send me a copy of this puzzle to review. Thanks!

Cast W-U has a very similar appearance to Cast Horse, except for two additional horseshoes that have been added perpendicular to the original horseshoes. As you may imagine, these get in the way a bit if you just try to do the original Cast Horse solution. Also, there are little knights on either end that get in your way a bit.

I was curious to see how much more difficult it would be. I fiddled with it for a bit, and was able to solve it pretty quickly, since I already knew how to solve Cast Horse. The added difficulty is pretty minor, since you can sort of see what needs to be done to overcome the obstacles. As such, I don't think it quite deserves the 3/6 rating, and should probably be a 2/6 like Cast Horse.

I think due to the extra volume that the pieces take up, they needed to make them quite a bit smaller than the horseshoes in Cast Horse. As a result, the puzzle has a flimsy feel, not at all like most of the Cast Puzzles series. That, in addition to the fact that the solution isn't that much more interesting, makes me not inclined to recommend this one unless you're really curious about horseshoe puzzle variations.

April 18, 2011

Cast Horse

Cast Horse is Hanayama's version of a puzzle any puzzler is sure to recognize. It is a very popular design for a good reason! Puzzle Master was kind enough to send me a copy of this puzzle to review. Thanks!

Since this is a classic design that is in the public domain, a ton of companies produce different versions of this puzzle. This version from Hanayama is quite nice if you are looking for something that you can slip into your pocket. It has a great weight to it and is just the right size. I also really liked the shiny finish that they selected.

If you want something a bit larger, check out  Old Shackles from Tucker Jones House Tavern Puzzles. I've played around with it a bit, and it is nice, but I think I prefer something a bit smaller and more compact, given that puzzles are currently over-running my small apartment!

As a puzzle, this is a true classic. When you first hand it to somebody who hasn't seen it before, the obvious reaction is that it looks impossible. Clearly the loop can't fit over either horseshoe, so how could it come off? This is a great quality in a puzzle.

Another great aspect is that you can, with a bit of practice, quickly take the ring off in front of somebody who is stumped, and it won't really help them very much. A bit like magic!

I remember when I first tried the Tucker Jones version this puzzle at Eureka Puzzles in Brookline, I had a heck of a time with it at first.  Then when I finally got the ring off, I found that it was just as tricky to get the ring back on because I didn't quite understand how I got it off. I tried to undo what I did to get the ring off, but it just ended up slipping back off again!

Overall, Cast Horse is a fun little puzzle that is definitely worth checking out, in whatever version appeals to you. I don't think there are really any downsides to it, other than the fact that most puzzlers will already have a copy (or several!).

I've seen a 3-horseshoe version (Three Levels of Dread a.k.a. Triple Crown) that sounds interesting based on this thread on Puzzle World Forums. I'll have to check it out sometime! My next post will be about another variation on this puzzle by Hanayama called Cast W-U.

April 17, 2011

Cast Helix

I purchased Cast Helix by Akio Yamamoto about a year ago, back when it was first introduced by Hanayama. Since I am a big fan of their Cast Puzzles series, I was quite interested to see what this puzzle would be like.

The object is to remove the coil from the star shaped piece. This piece has two components that pivot with respect to one another. The back looks pretty much like the front, and the intersection of the grooves in both pieces leaves holes for the coil to rotate into, sort of like Wuurm.

I played with this one for a while and didn't have much luck until I noticed that I could easily remove the ring by putting it in any of the five inner holes, and lining up the other side of the ring with the adjacent crotch of the star. Since this didn't appear to have anything to do with the orientation of the two pivoting pieces, I was pretty sure it was a false solution. Indeed, when I peeked at the solution sheet, it was not correct. George Bell had a similar issue that he mentioned on this thread at Puzzle World.

I played around with it for a while longer and still didn't have any luck, so I decided to actually look at the solution sheet, which I avoid, but it felt like something didn't seem right. I tried doing the solution as described on the solution sheet, and it didn't work! Somewhat annoyed, I shelved this one and only took it out again yesterday to have another crack at it.

This time, after again playing with it for a bit fruitlessly, I looked up a YouTube video solution. The Hanayama solution sheet wasn't that clear, so perhaps I was just doing something wrong. Even with a very clear solution video, it still wouldn't work! Finally it occurred to me that my ring must be bent: this had the dual effect of allowing a false solution while also not allowing the correct solution! How annoying!

I tried to bend it just a bit to close the gap in the coil, and that did the trick. It has to be just right for the solution to work, and mine was a bit off. A few people on Puzzle World and YouTube cite similar problems, but I'm not sure how pervasive it is. Even after correcting mine, it does require a bit of force to execute the solution, which too bad. Based on this experience, this is one of the few Hanayamas that I would say not to bother with, unless you just want to collect the whole set.

April 16, 2011

Cast Disk

Cast Disk is another maze-type puzzle designed by Oskar van Deventer for the Hanayama Cast Puzzles series. Thanks to Puzzle Master for sending me a copy of this puzzle to review!

It wasn't obvious to me how it would work based on the picture, so I was interested to see how it worked. When you're actually holding it, you'll quickly notice that the two disks slide away from each other along the axis where they intersect (similar to Cast Keyring), but stop just before they separate.

Depending on where you are in the "maze" you can rotate one disk or the other, restricted by the shape of the square-ish holes in each disk and the shape of the lip around the outside of each disk.

With a puzzle like this, you could come up with a map of the different states the puzzle could be in, and the paths between those states to exhaustively find the solution, as George Bell did in an article on his webpage.

This is useful for really analyzing the design of the maze: a good maze will give you a number of opportunities to go wrong direction and either get stuck or go in a circle, and you can see those circles in George's map. It can be all the more tricky for puzzles like this, where your location in the maze is not obvious.

I fiddled this one for about 5 minutes before solving it, though I wasn't entirely sure what I had done. I could tell where the end point in the maze was, so it was just a matter of blundering in that direction until I finished. This is the way I usually solve puzzles like this, and usually with repetition I can figure out what it was that I was doing, though I haven't done that with this one yet. I thought that Oskar did a good job of adding loops to tempt you into taking the wrong path.

Interestingly, George also noted that you can flip the orientation of the pieces after disassembling them, and still be able to return to the starting position where the disks slide together, though the solution path will be different. I'll have to try that sometime!

Esthetically, this puzzle felt a bit less sturdy than some of Hanyama's other puzzles, mainly due to the thinness of the disk. I also found the squared off edges a bit less pleasing in the hand than a nice curvy puzzle like Cast Baroq (one of my favorites!).

This is a fun design that is worth trying out, but I'd go for some of the more interesting of Oskar's maze-like designs first: Cast O'Gear and Cast Cuby are both quite nice and have very unique movements and a bit more difficult.

April 15, 2011

Kamei Small Box #3

I purchased Small Box 3, designed and made by Akio Kamei, at one of Nick Baxter's auctions a few months ago (photo by Nick). There were a few other Karakuri Creation Group boxes that I was bidding on, but they all went somewhat above what I wanted to spend, except for this one!

I was intrigued by this one because of its small size, I tend to like small boxes, since it makes you wonder how much of a mechanism could be hidden inside. This one is beautifully crafted from rosewood, and in quite good condition. It was made as Kamei's Christmas present back in 2002, things seem to have gotten much more ornate since then!

I was a bit disappointed to find out that the mechanism is actually the same as Karakuri Small Box #7 (shown here), but it is my own fault: it is listed right in the description for #7 on the Karakuri Club website. It does, however, look quite a bit nicer due to the rosewood construction. Also, the mechanism of this box is better disguised than in Small Box #7, which I liked. Fortunately, Small Box #7 is one of my favorites in the Karakuri Small Box series.

The mechanism itself is quite nice, and had a smooth movement. The first move is pretty easy, the second move is somewhat unusual, and the final move is quite unique. Overall, a cute little puzzle that has a nice solution and is well crafted. Since they have been sold out for a while, it may be a bit hard to come by this particular box except at auction, but you can get most of the enjoyment from purchasing Karakuri Small Box #7, which can be bought directly from the Karakuri Creation Group or through a distributor like Puzzle Master.

April 13, 2011

Cast Cricket

Cast Cricket is another puzzle in the excellent Cast Puzzles series by Hanayama. It was based on a designed patented in England back in 1898 and was adapted for Hanayama by James Dalgety, who has the only world's only known remaining original version of this puzzle. Puzzle Master was kind enough to send me a copy of this puzzle to review!

I had refrained from purchasing this one for a while partly because I didn't quite understand how it would work. Just from looking at the picture, it didn't seem like it would be very interesting, but I should have known better! It actually ended up being a fairly good puzzle.

There are only two parts, the wicket and the spur of cricket bats, and the goal is to separate the two. You'll quickly notice that there are some protrusions on each cricket bat that keep this from being a straightforward task. You can rotate it around a bit and get it so that only one bat remains stuck, but that's the tricky part!

I played around with this one for a bit, and just ended up going in circles. After I stopped and thought about it, I was able to figure out how to proceed and solved it. Woo hoo! I think it took me a good 10 minutes though, which is more than I would have expected for a difficulty 1/6. I think this one should probably be a 2/6, since the solution is actually fairly subtle and the solution path is several steps long. The solution is good in that it takes advantage of a mental block that most people will have, which is a great quality for a puzzle to have!

I brought it to a dinner party, along with a few other Hanayamas, and folks seemed to have a good time with it. One fellow was quite vexed by it for a while, but eventually he was able to figure it out. I would say that on average, it took about 10-15 minutes for people to solve, if they had the patience to finish it.

As for the construction, due to the spindly nature of the pieces, it is quite a bit lighter than most of the other Hanayama puzzles, which makes it feel a bit cheap by comparison. However, while light, it does feel quite sturdy and you definitely would have a hard time forcing it or breaking it. One thing I don't like about this puzzle is the fact that it doesn't display particularly well. The base of the wicket isn't quite wide enough to stand it on end, and even then, the cricket bat spur wouldn't have anywhere to rest.

Overall, I thought Cast Cricket was a solid puzzle and enjoyed solving it. It is not one of my favorites in the series, but it is still worth checking out.

April 7, 2011

Tipperary by Jack Krijnen

Jack Krijnen was kind enough to send me a copy of a puzzle he designed named Tipperary. He sent it from The Netherlands in December and it finally arrived in February after we both thought it had been lost! Needless to say, we were both quite relieved. Thanks Jack!

It is an 18 piece burr which requires 43 moves to remove the first piece. Jack designed this burr back in 2003 and at the time it succeeded Burrloon (33 moves by Goh Pit Khiam) in highest level. Indeed, it is a long way to Tipperary!
As you may imagine with this number of moves, it was fairly difficult to get it apart. However, the solution does have a pattern to it that makes it pretty easy to remember once you get the hang of it. I think it took me a good 30 or 40 minutes to get the first piece out, and after that it is fairly easy to disassemble the rest of the burr.

As usual, with a burr of this complexity, I took great care to keep the pieces in the correct orientation as I removed them and also kept track of their position. However, when I tried to reassemble it, I arrived at a position where I couldn't figure out how a piece could fit in. Damn! I sweat it out for a while, but it soon became evident that I wasn't going to be able to figure it out. Abandoning hope, I mixed up the pieces in frustration, and then proceeded to sort them by shape. It was actually an interesting exercise, since I previously didn't really understand its construction. Here's a photo of one of the more complex pieces.

If you look at the cluster of six pieces going in the same direction, the two outer pieces and the two inner pieces are essentially the same, which gives the solution a nice symmetry. However, figuring out the location of the remaining six 'inner' pieces is still quite a challenge.

Jack actually wrote an article for Cubism for Fun that described his the design process for this burr, which was quite interesting to read. This "cage" concept for the outer pieces was actually created by Willem van der Poel way back in 1953! The article describes how Jack originally discovered a short sequence of move involving two pieces, and how he drastically increased the move count by adding in a second sequence of moves that interferes with the first sequence. This essentially multiplies the two move counts together, resulting in the length.

The real challenge was to figure out how to make the solution unique, and for this he used a computer to evaluate over a half-million potential assemblies for uniqueness. In the end, he did discover a version that had a unique solution, which is the version posted on Ishino Keiichiro's site, Puzzles Will Be Played. The version he sent me, however, is a bit easier to construct and has four solutions, all of level 43.

So, I was left with a bunch of pieces and no idea how to put them back. Fortunately, there's a great tool named Burr Tools that can solve puzzles like this quite quickly. To my surprise, it actually took a while to solve, about 20 minutes. Usually, it can come up with a solution to a simple puzzle after only a few seconds, so that shows you how complex a process it can be to solve an 18 piece burr!

Using the solution generated by Burr Tools, I carefully put the puzzle back together. It was a bit of a dexterity challenge though, since I had to keep reaching for the keyboard to navigate through the solution while holding the burr in my other hand, hoping it wouldn't fall apart! Eventually I did get back to a position where I could finish it off: I still remembered how the last few pieces went in. Phew! It was quite a relief to get it back together.

Jack did an excellent job constructing this burr, the fit is quite good, and it is not an easy burr to make either! The piece shown here has an inside corner that must have been made square with a chisel. Very nice! The wood he used was Meranti, which Jack says is actually not a very good wood due to tearout when cutting. It has a somewhat unusual aroma, too.

I had a great time with this puzzle, though burrs aren't my specialty, it was fun to play around with this one for a while. About a year ago, Jack developed the Burrly Sane series of 18-piece burrs, that have outrageously long move sequences to remove the first piece:
I will have to try to tackle one these some day, I'm quite curious how they work. Interestingly, they actually have fewer assemblies than Tipperary (which has more than half a million). These have somewhere between 1 and 40 assemblies, which is much more reasonable to evaluate by hand. Of course, finding the assemblies to evaluate in the first place, and then eliminating the ones that don't have valid disassemblies is another problem! A puzzler named Guillaume Largounez has been posting on the Puzzle World Forums about his experiences with various extremely difficult burrs, so check that out if you're interested in reading more. Also check out this section of Rob Stegmann's Puzzle Page for more information on 18-piece burrs.