September 30, 2009

Cast Equa and The Fifth Chair

After I got back from Costa Rica, I headed down to Eureka to pick up a few more puzzles. David, the owner was there, which is always nice because he tends to have good recommendations. I told him that I was thinking about picking up another Hanayama, and he suggested that I give Cast Equa a try. It was one of the newer puzzles from Hanayama, designed by Oskar van Deventer, and was supposed to be quite challenging.

We chatted for a bit and he mentioned that the person who designed Thinkfun's Aha! The Fifth Chair had stopped by the shop yesterday. David said that it was not too difficult but was an interesting little puzzle. I decided to purchase both Equa and The Fifth Chair and headed back home to try them out.

The Fifth Chair first is an assembly puzzle where the objective is to use the four chair-shaped objects to create a larger fifth chair that has the same proportions of the smaller chairs. This is an interesting puzzle because each incrementally larger chair has double the volume of the previous chair. So you are given two small chair (volume of 1 unit, lets say), one medium chair (volume of 2 units), and one large chair (volume of 4 units).  The resulting chair has the same proportions and will have a volume of 8 units (1+1+2+4).

I played around with this one for few minutes and wasn't making much progress. Eventually I took a somewhat more logical approach using the idea that the proportions should be the same, which ended up working. I like puzzles where a logical approach is effective because I find it more satisfying than just fiddling with something until it randomly works out, so bonus points for that.

Next I tried Cast Equa. It is a good looking puzzle that has a nice symmetry to it. The central spherical shape can rotate on the two posts sticking out of the ends of it. It is not immediately obvious how to even approach this one: I played around with it for about an hour and didn't have much luck. I found a few 'moves' but they didn't seem to get me anywhere productive.

I worked on this one on and off for a week or two and was really getting frustrated. Eventually I finally got it apart while sitting around waiting for a doctor's appointment. This was really exciting, but I was stumped as to what I did differently: I was just doing one of the moves that I had done before and all of a sudden it worked!

After studying it for a bit, I finally figured out what had happened. I can't say much more without giving away a hint at the solution. I think that the solution was a bit too tricky for my taste: it would have been appropriately difficult if the solution was just slightly more apparent, but that is just a matter of personal preference. Be prepared to spend some serious time with this one if you attempt it! Check out Oli's review of Cast Equa here.

Tomorrow I'll talk about some puzzles that I won in a raffle over at Eagle's Woodworking Forum.

September 29, 2009

Costa Rican Wire Puzzles

As I mentioned in my post about Danlock, I traveled to Costa Rica for spring break, which was a lot of fun. I actually have a travel blog here (March 2009), so check out that if you're interested, but I'll skip straight to the good bits: I encountered a street vendor in the town of Puntarenas selling a variety of wire puzzles that he had made!

Needless to say, I was quite excited: I was abroad and going through puzzle withdrawal (I think I had solved Danlock by this point). I walked over, and saw that he was showing the classic ring-and-spring puzzle to curious onlookers. He would demonstrate how he could easily remove the ring from the spring, then he would hand it to an onlooker who couldn't do it.

He saw that I was interested and handed me one as well, of course I know the trick so I popped the ring off quickly, before anybody could see what I was doing, and showed it to him. He chuckled and asked if I would like to try something more difficult, of course I said sure!

I guess I should mention now that he only spoke Spanish, and I speak very little Spanish, but I could get the gist of what he was saying. Fortunately the word difficult sounds the same in Spanish. Hooray for cognates!

He handed me the puzzle shown here, which I don't know the name of. I need to get Dick Hess' Compendium of Wire Puzzles so I can look this sort of thing up! Anyways, I fiddled around with it for a while and was unable to solve it, much to his delight. I told him that I'd like to purchase it and asked him (as best I could) to recommend something else that was very difficult.

He pointed me to the puzzle shown here, which I think is also known as Rat Race. I couldn't quite make out what he was saying, but it had something to do with a labyrinth and the fact that this was a difficult puzzle. Enough said! I'll take it! I think I paid him something like $1 for both of the puzzles: in hindsight I should have bought a bunch, since this was a great deal. Oh well, next time!

After making my purchases, my girlfriend and I headed over to a nice little spot for lunch. I played around with the easier of the two puzzles for about 15 minutes and eventually figured it out! Here's a picture of me ignoring my frozen margarita in favor of this $0.50 puzzle. I had a lot of fun solving it: definitely a good value in terms of dollars per minute of puzzling fun.

The second puzzle I played around with for a bit, but didn't have much luck with. I set that one aside and worked on it again on the bus ride back to the capital city, San Jose. Fortunately, the bus ride was quite long, I think about four hours.  I worked on damn puzzle nonstop for about an hour and a half before I finally figured it out. This one is tricky, but quite enjoyable!

Tomorrow, another ridiculously hard Hanayama that took me forever to solve.

September 28, 2009

Lonpos 303

I was down at Eureka with my girlfriend and while I was browsing she started playing around with a plastic packing puzzle named Lonpos 303 that they had on display. She doesn't generally care much for the puzzles that I had been buying, so I was happy to see her enjoying this.

After I had finished browsing, I walked back over and saw that she was still working on it. At first, we thought that the idea was just to get the pieces into the rectangular box, and of course you can do that, but it is quite challenging.

After playing around a bit, we found out that the little booklet that we had been ignoring contained a number of preset 'problems' where a number of pieces were already laid out and your task was to find the positions for the remainder of the pieces.

The problems were ranked in order of difficulty, which was equal to the number of pieces you needed to place. This was cool because you could make the puzzle as easy or as hard as you want, depending on your skill level. I'm sure a lot of you are familiar with this concept, but at the time I was quite excited that this kind graduated difficulty puzzle existed. Here I had been spending $12 on a puzzle, but this $20 puzzle was 300+ puzzles in one!

Another cool thing is that you aren't just limited to the flat rectangular packing problem: if you flip the case over, there is a 5x5 grid of holes that you can use to build a pyramid! Again, the book had a number of pyramid problems laid out. So the puzzle was both a 2d and 3d packing puzzle with lots of different problems to solve. We both thought this was great and ended up buying the puzzle.

We've had a good time with it: the fact that it has a carrying case and such makes it quite easy to take on trips and such. The round colorful pieces are nice as well. The only gripe I have is that it isn't the sort of thing you would want to be fiddling with when you might need to pack up and leave quickly, like if you are waiting for your airplane to board. The box won't close until you solve the problem at hand, so you either need to figure it out or use the picture on the front of the booklet to place the pieces. That said, I like how everything packs away neatly and compactly, so I don't think I would change this to make it easier to put away quickly.

This puzzle has won a number of awards (source):
  • Oppenheim Toy Portfolio Gold Seal 2007
  • Dr.Toy's 10 Best Games 2006 Award
  • Creative Child Magazine's Top Toy of the Year Award (Brainteaser games category) 2006
  • Parents' Choice Foundation's Gold Award 2006
  • Mr. Dad's Seal of Approval 2006
  • Toy Tips Mark of Excellence 2007
  • iParenting Media Award Winner 2007
  • The National Parenting Center Seal of Approval 2007
  • Major Fun Award 2007 (Thinking Games)
  • The Toy Man Seal of Approval and Award of Excellence and Editor's Choice awards 2007  
Another similar puzzle that I don't have yet is Lonpos 84T: it is a big puzzle that is similar to Lonpos 303, except that it is more of a coffee table puzzle than something you would want to tote around with you. This thing is big! They have it on display at Eureka, but since it costs $80, I don't think I'll be purchasing it any time soon. $50 I could do, but $80 seems like a lot for what it is.

ThinkFun makes a lot of these types of graduated puzzles, such as Rush Hour and River Crossing, which are also cool. I don't own either of these (yet), but I've played around with them a bit and they are entertaining.

Tomorrow, I'll write about some handmade wire puzzles that I bought from a street vendor in Costa Rica.

September 27, 2009

My First Puzzle Auction

I had signed up for the mailing list over at, and was excited to hear that the next puzzle auction was under way, so I headed on over to their marketplace to see what was for sale. There were all sorts of great puzzles, but unfortunately they were a bit out of my price range: keep in mind I had gotten accustomed to spending $12 for a Hanayama, so everything above $30 seemed steep.

I did end up buying one thing: a dexterity maze from Tom Jolly named Quicksilver Maze. It had a bit of mercury inside, and you roll it from one end of the maze to the other. I won it for $5, which seemed like a pretty good deal. So what if it can kill me? It is liquid metal!

It arrived a few days later and I had a good time playing around with it for a bit. Not amazing of course, but what do you expect from a $5 dexterity maze? I still thought it was a good buy and now I have a vintage puzzle in my collection!

There were a bunch of great puzzles for auction, but what really caught my eye was the listing for a puzzle called Danlock by Dan Feldman from Israel. The description pretty much made it sound like the best puzzle lock ever, and I'm a sucker for something that comes highly recommended.  Here is an excerpt from Edward Hordern's review in Cubism For Fun (CFF) No. 45:

If I had to give away my entire collection of locks (there must be a hundred or two hundred of them) and keep only three, this recent acquisition would be one of them. ... To my way of thinking, the new lock is easily the best of the modern padlocks...
I really liked the sound of that, but unfortunately the $150 that the locks went for at auction was way more than I was willing to spend. However, on Dan's site it showed that there were a limited number available for sale. I was quite psyched to see this but as I'm sure you know, puzzlers frequently go a long while without updating their sites, so I didn't get my hopes up.

I contacted Dan and he did indeed have some Danlocks in stock for $80 including S&H. I was really excited to hear this since I was drooling over this puzzle the whole time the auction was running: I couldn't get my check in the mail fast enough!

There are two variations, Danlock A and Danlock B, and he told me that B was somewhat more difficult. I don't like the idea that there is a harder version out there, so I went with version B. From what I understand, there isn't really much point in having both because they are quite similar.

My lock arrived a week or so later, and I couldn't wait to give it a try! It had a great feel to it: it actually seems like a modified real lock, not like one of those cheaper trick locks from India. It came in a nice bag with Danlock written on the outside. (Note: this writing rubs off easily, so be careful! I kept it in this bag in my backpack and now all the writing has rubbed off). As you can see in the picture, one key is broken and the other is locked to the shackle!

I got the first of the three steps quite easily, it is pretty much the first thing I think anybody would try. However, now the difficulty becomes getting the lock back the way it started! This proves much more daunting than you would expect. Unfortunately, I had to catch a flight to Costa Rica for spring break that evening, so I had to stop solving and head to the airport.

I played around with it on the flight a bit, but didn't have much luck. I thought that you needed to listen to what was going on inside which was hard to do with the noise on the airplane, so I set it aside and got some rest.

I worked on it a bit more in Costa Rica the next morning and finally discovered the second step. I think it probably took me over an hour, but it was quite satisfying when I finally figured it out. Now I was stuck on the third step! Fortunately, I know better than to sit around indoors in Costa Rica, so I set it aside for a bit and went to see the sites. It was waiting for me when I got back, but this last step proved quite challenging!

I worked on it for 15 minutes here and there during my trip, and finally a few days later discovered the solution. What a journey! There is a reason people praise this puzzle so highly: it is truly great!

As far as difficulty, it is challenging but doable by most, I would think, if you are willing to spend some time with it. Overall, an extremely cool puzzle. This would be the jewel of my collection for quite some time! I loaned it out to a friend of mine who enjoyed this type of thing more than my other friends. He had a great time with it. I also loaned it to David, the owner of Eureka, who also said he (and his staff) liked it quite a bit.

Lets hope we see more great locks from Dan Feldman! I am sure there are plenty more great ideas where that came from.

After reading this, you might think: why not buy them for $80 and then auction them for $150? I had this thought, but had a feeling that this was probably frowned upon. Since I didn't want to go upsetting people, I checked with Eric Fuller who runs CubicDissection for his take on the issue. He agreed that such a thing was probably likely to irritate people, and I didn't have much interest in irritating people.

Tomorrow, I'll write about a puzzle I found that my girlfriend actually enjoyed as well!

September 26, 2009

Cast Laby and Cast Heart

Next I picked up Cast Laby and Cast Heart. David, the owner of Eureka Puzzles, had recommended Cast Laby. From looking at it, I thought that I had a pretty good idea of what the solution would be: it is basically just a double sided maze, so how interesting could it be? He assured me that it was an interesting puzzle, so I decided to give it a try.

This puzzle was re-designed by Nobuyuki Yoshigahara based on a 19th century British design. As it turns out, the puzzle was actually quite interesting. I tried to solve it just by wandering around in the maze, but that approach proved futile. Perhaps you will be more lucky, but I had to take a systematic approach to make sure that I tried every possible path before abandoning a particular starting point. There are multiple places and orientations where you can enter the maze, which makes it more challenging.

The pins on the piece that you navigate through the maze are offset, so you need to rotate the piece around to get them in the correct orientation. There were two moves that I thought were particularly clever, I appreciated that Nob went to the trouble of making the solution interesting: it would have been easy to come up with a fairly simple maze but it is clear that he put some effort into making it challenging and as interesting as possible.

This puzzle is rated a 5/6 on the Hanayama difficulty scale, and I was suprised to find that I agree with that rating. It took me about an hour to take it apart and maybe a minute to get it back together because I paid such close attention when I was taking it apart. If you find the solution by luck, it might be challenging to get back together, particularly if you don't know which exit you came out of! Check out Oli's review of Cast Laby here.

Cast Heart was another one that I wasn't entirely sure about. It is very different from the other Hanayamas because of the flexible chain. I thought that it was worth trying, since I was enjoying almost all the Hanayama puzzles so far, this one was probably good as well. Note: the chains are not connected like it appears in the picture.

I didn't like the physical appearance of this puzzle quite as much as some of the other Hanayamas: it looks a bit sloppy when lying around on your desk. I think I would have gone with a smooth finish on the big heart rather than the studs around the outside. Also, the small  heart sits in a groove in the large heart, but it takes a bit of fiddling to get it to line up right because the chain gets in the way. It would have been much better if there were magnets to hold it in place. Also, the chain is a bit coarse, which makes it harder to manipulate.

That said, the imagery of "the tight bond holding together the hearts of lovers the world over" is kind of nice, I suppose. There is something about the chain that makes the bond seem oppressive, however, but I digress!

The solution to this puzzle is actually quite nice, at least for me as a novice disentanglement solver. When solving this, I had to fiddled with it for a while before I noticed that I needed to think outside the box. I think people experienced with disentanglement puzzles will find this fairly easy, but I would agree with the 4/6 Hanayama rating. It took me about 20 minutes to solve, I think.

Tomorrow, I'll write about two puzzles that I bought online: one from an auction and an amazing puzzle lock made by a puzzle designer in Israel!

September 25, 2009

Cast Quartet

After solving those two level 6 Hanayamas (kind of), my confidence was high so I decided to try the final level 6: Cast Quartet by Mineyuki Uyematsu. This puzzle was an entry in the 2007 Puzzle Design Competition at the International Puzzle Party. I went down to Eureka Puzzles to pick it up and headed back to my apartment.

The puzzle has a nice black finish to it and an interesting angular appearance. It has a good weight to it as well, as do many of the Hanayama puzzles.

Based on the reviews I knew it was going to be a very challenging puzzle, so I tried to be very methodical when I was taking it apart: this type of puzzle can be a beast to put back together when you don't pay attention (as I found with Cast Vortex). Unfortunately, I was paying such close attention that I wasn't able to get the damn thing apart! I think when I get very focused on the movements, it limits my creativity somewhat.

So I abandoned that approach and just started wiggling it around in various ways, and eventually it started to come apart. There are multiple levels of 'apart' for this one, and it took a decent amount of effort at each. Once it finally came undone, I knew I was in trouble: I really had no idea how I had done it.

One cool thing about this puzzle is that you can form a secondary shape using the four pieces that is kind of cool, but it isn't particularly challenging. I admired this for a bit and then set myself to the task of putting it together.

I worked on putting it back together for several days to no avail, it was essentially a jumbled mess that I could not make much sense of. Eventually I gave up and took a peek at the solution to get me going in the right direction. I worked a bit more knowing that I had at least started correctly, but it was still an overwhelming task. This one was tough!

Even looking at the directions I couldn't get past this one particularly tricky move and had to resort to YouTube. That helped and I was able to get it back together, but that was somewhat less satisfying because of all the help I needed.

Overall, I would recommend this one with slight hesitation: personally this one was past my 'too hard' threshold, so unless you're quite good at this type of puzzle I wouldn't recommend it. Also, I'm not sure what it was, but after the hours of playing with the puzzle, the finish now looks a bit blotchy. Might be my moisturizer or something interacting with the metal but I can't get it back to its original gleaming state.

Tomorrow, I check out two puzzles that I was a bit hesitant to try at first but ended up being pleasantly surprised.

September 24, 2009

Cast Enigma and Cast News

As I was getting more into the Hanayama series, I had read through a lot of the comments on PuzzleMaster and was getting pretty familiar with even the puzzles I didn't own yet. I had read a lot about Cast Enigma and Cast News, so I decided to pick them up on my next trip to Eureka, my local puzzle shop.

Cast Enigma, designed by Eldon Vaughn, came highly recommended by David, the owner of Eureka, so I knew it was going to be a great puzzle. Based on the comments at PuzzleMaster, it was considered to be one of the hardest of the Hanayamas, so I was definitely in for a challenge. The puzzle itself has a decent finish, though its appearance is less elegant than some of the other Hanayamas. It doesn't have a nice appearance when sitting on a shelf: it just looks like a jumble of metal. A puzzle like this really needs to be hung.

The solution to this one is very nice because it is lengthy, but you have some sense of progress. There are some dead ends, however, which makes this one more challenging than Cast Baroq. I found this puzzle to be fairly similar to the ODD Packing Puzzle I described yesterday: as you play around with it, you build an understanding of how the pieces interact and restrict each other, which helps you move along.

I think this one took me about an hour, maybe a bit more, to take apart and put back. I definitely agree that it is one of the hardest Hanayamas. I found it to be of similar difficulty to Equa, News, Quartet, Vortex (see my blog entry about Vortex). I would definitely recommend this one!

I thought Cast News was going to be a real beast: it had no visible moving parts, but you could hear things shifting around inside. It has a nice appearance with a good weight in your hand. I was particularly daunted by this puzzle because the comments on PuzzleMaster suggest that it took a very long time for some people to solve this one. This puzzle was designed by Nob Yoshigahara at 19 years of age!

I tried what I thought was a fairly obvious thing to try with a hidden mechanism puzzle, and lo and behold it opened! I was curious as to why people were having such trouble with it when I solved it so quickly. After more inspection, I determined that my puzzle was missing half of its locking mechanism! There were locking pins that were supposed to be there but weren't, which made it a much easier puzzle. This was quite disappointing because now I'll never know if I would have been able to solve the puzzle as it was designed, since the solution is apparent once you see the mechanism.

I checked the solution on PuzzleMaster, and indeed, my puzzle did not require a second step to open! I scoured the web to see if I could get an explanation of what the mechanism should be (I had a good idea, but was curious).

I found a website where the author discussed his theory as to the inner workings of the puzzle. I won't link to it here since it would spoil the puzzle for you to see his page, but you can probably find it by searching if you'd like. Since my puzzle was already broken, I decided to disassemble it to confirm or deny his hypothesis.

It took a hammer and a screwdriver, but I was able to pry the cover off of the mechanism and confirm that my pin was indeed missing: it hadn't slipped back and gotten jammed. He wasn't far off on his theory, but I thought he would be curious, so I sent him a few pictures that he posted on his site.

I had bent the panels a bit when removing them, but I was able to bend them back with a set of pliers before I hammered them back into place. Definitely don't do this with your puzzle: you can't really do it without getting some scratches on your puzzle.

Eureka was kind enough to take my broken News in exchange for a new one, but unfortunately I missed out on the experience of solving the full puzzle. As such, I can only hypothesize that this would be a very hard puzzle to solve, but I am sure it is well worth it! Check out Oli's blog entry about his experience with Cast News.

Tomorrow: I attempt the last of the level 6 Hanayamas!

September 23, 2009

Odd Packing Puzzle

I was down at Eureka one day and ran into the owner David Leschinsky. He is frequently at the shop and I enjoyed chatting with him about the different puzzles he has available. He is quite knowledgable and I am always quite happy with his recommendations. Today among other things, he said that he thought I would enjoy a puzzle by Hirokazu Iwasawa (Iwahiro) named ODD Packing Puzzle.

It wasn't much to look at: the wood was very precisely cut but unfinished. I looked at the price and was a bit suprised that it was $40, since it wasn't particularly elaborate. I had gotten used to spending about $20 per visit to Eureka, so this seemed like a bit much.

The description from David sounded great, though: he said that as you worked with the pieces, you develop an understanding of how they interact with each other as well as with the box. After a while, you begin to understand what is possible and can work out the solution. That was interesting, and it had won the grand prize in the 2008 Puzzle Design Competition at the International Puzzle Party, so I decided to give it a shot.

I started on it night away when I got home, and had a great time with it. I think it ended up taking me about an hour. Just as David said, you start to realize what is possible and what is impossible after playing around with the pieces for a while, and I was stumped as to how it was even possible to get all three pieces in. Instead, I decided to think about it backwards: how could they all fit, and how would I get them out if they were in there. This approach proved effective and eventually led me to the solution.

Overall, a fun puzzle that I would recommend. I have loaned it to my father and a friend who both were able to solve it and they both enjoyed it as well. It is not really the type of puzzle that you can just fiddle around with and expect to solve, which I like. It really helps if you have a decent amount of time to sit down and think it through.

Tomorrow, I decide to step it up a notch and try two of the hardest Hanayamas.

September 22, 2009

Cast Elk and Cast Radix

After a great Christmas break full of puzzle building, I headed back to my apartment in Brookline for school. Of course, as you recall, I am a brief 10 minutes away from Eureka Puzzles, so I couldn't help but head back down there to pick up a few more puzzles.

I had read good things about Cast Elk, so I decided to pick that one up along with Cast Radix, which looked appealing. Cast Elk was a very cool puzzle (the designer is unknown, I think). I fiddled with it for a bit, but since it was a Friday night, I ended up going swing dancing (as I usually do).

The dance was good, but I had the puzzle in the back of my mind: when there is an unsolved puzzle around, I have a hard time resisting it! Fortunately, I brought it along and found some time to work on it later in the evening between the swing dance and a late night dinner at IHOP afterwards.

I convinced my very patient girlfriend to sit tight for a minute while I tried 'one more thing' that I had thought of while dancing. And sure enough, it worked! Quite a relief, now I could continue with my life.

I really like puzzles that only have two pieces, such as this one, because it makes you think "how could this be difficult?"  Many of the Hanayama series are of this nature, which I think is why I enjoy them so much. You go from "how can it be hard?" to "how can it be possible?" in about 5 minutes. There is a great article about two piece puzzles written by Serhiy Grabarchuk, Jr. on a site called that can be found here. Also, check out Oli's review of Cast Elk.

The second puzzle, Cast Radix, had a very cool design by Akio Yamamoto. Unlike most Hanayama puzzles, which kind of lay down, this one stands boldly upright like a piece of modern art. It has three parts, two loops and the base which hold the pieces in place. It has the same nice finish that Cast Baroq has (also by Yamamoto). It won the Grand Prize in the 2005 Puzzle Design Competition at the International Puzzle Party.

The solution is interesting and I found it to be more difficult than Baroq simply because it has more 'dead end' paths that you can follow. There was some force required on one move that I think detracted from the puzzle somewhat. Still enjoyable and worth buying, though!

In tomorrow's entry, I'll talk about my experience with an award-winning puzzle from Japan.

September 21, 2009

Puzzling Serendipity

In my first entry on Frand's Mind Bender, I mentioned that the concept was created by Jay Scott, but this was actually information that I later came across after much searching. Originally, I only knew that it was created by a character on LambdaMOO named Frand, who had not been active on the MOO for many years.

After I finished creating my physical version of this virtual puzzle, I thought it would be nice to figure out who this Frand is, since he would probably get a kick out of what I had done. I asked around on the MOO and got the suggestion to search on another MOO that many old LamdaMOOers used to frequent.

I asked around there, and had no luck. Another MOOer suggested that I contact one of the founders of LambdaMOO, Pavel Curtis. I searched around the web for him, and it turns out that he has a puzzle blog named Pavel's Puzzles. He has actually designed quite a number of puzzles that are available for sale on his website and is an IPP member.

One that particularly caught my eye was Octamaze. He describes it as a multi-stage puzzle where each stage leads you to the next until you finally arrive at a satisfying conclusion. This sounded like a lot of fun, so I ended up ordering one from him at a very reasonable price of $15.

When it arrived, it came with a piece of paper that said "The answer to this puzzle is a four-letter word. Can you find it?" In addition to this information, on his website he says that the puzzle was made to be exchanged at Gathering for Gardner 8 (G4G8), so the puzzle has a strong "8" theme to it.

I had a great time solving it, though I did need to make use of the hint page on Pavel's site. The hints are provided as a sequence of pages that gradually guide you towards the solution. The first step (you can probably guess what it is), was quite time consuming but straightforward. I had the right idea for the second step, but overlooked a key detail (I needed a hint here). The final step is fairly straightforward once you figure out the previous stage, but it is quite satisfying.

Overall, I would say this is a great example of ingenuity in the puzzle community and a solid buy. Pavel has produced a number of other multi-stage puzzles that look like fun, though I haven't tried them. Let me know if you have!

As you can guess, I did end up tracking down the real name of the designer of Frand's Mind Bender, Jay Scott, but it wasn't through Pavel. Another MOOer recalled that Frand used to publish a series of short satirical pieces called the Daily Whale and it turns out he had a website with the same name that we found on Google. Isn't technology grand?

Tomorrow, I'll write about another trip down to the puzzle shop and where I pick up a few more Hanayamas.

September 20, 2009

Frand's Mind Bender (Part 2)

Check out Frand's Mind Bender (Part 1) if you are just joining us.  In the last post, I describe the origins of the puzzle as well as how I ended up with the components I used to build it.

I ordered the display I selected and it arrived a few days later. Now that I had all the components that I needed, I actually needed to figure out how I was going to implement these special knobs that one could push, pull, twist left, and twist right.

Unfortunately, these knobs were not the type you could purchase at an electronics store, though I did look around a bit. These were not typical knobs: I needed them to spring back to position after you twisted them, more like a jog wheel on an old school blackberry than a dial than a volume dial on a stereo or something.

I ended up custom building them, as shown on the right. Each knob is connected to a dowel. This dowel runs into a block of wood. A smaller dowel is inserted into a hole that is drilled in the larger dowel, so it is perpendicular to the dowel. This peg interacts with the tactile buttons that are screwed into each side of the block of wood. They had a nice click to them so you can feel when you have made the connection, which you can actually feel all the way down the knob.

The blocks were pretty tricky to make: I had a friend Patrick Sheehan who is a carpenter help me out a bit with these, since I wasn't quite sure how to go about it.

I brought my measurements over and he had a piece of stock that was the right width and height already (I think .75x.75). Using a dado, he cut a groove down the center of the stock. Next, he turned the stock 90 degrees and used the dado to cut a perpendicular groove. Finally, he cut the finished block off using a chop saw.

This probably would have taken me an hour and several fingers to figure out, but he was done in about 5 minutes. All I had to do next was drill a vertical hole and a horizontal hole, and the blocks were completed.

I wasn't quite sure how I was going to attach the switches to the block, since they don't really have any type of mounting hardware. I ended up using a jigsaw to cut out small pieces of circuit board. Then I screwed the circuit board to the blocks and soldered the switch to the circuit board. Fortunately, there isn't much stress on the solder in this position, so it is quite sturdy.

One thing that was a huge pain in the butt was that the holes on the circuit board weren't quite big enough for the screws I had, so I had to pre-drill all these holes. That's 2 holes per board, 4 boards per block, 4 blocks in the puzzle for a total of 32 holes, which took a while.

As if that weren't tedious enough, each switch needed 4 solder joints. I'm not going to bother explaining the connections, but suffice it to say that it was fairly complex. This made for a total of 64 solder joints. Did I mention that I didn't know how to solder? I was getting pretty good by the end though! Here is a picture of the whole array of switches and the mess of wires that connect them.

I connected the switch matrix up to the display, and wired the display to the microcontroller, and amazingly it all worked! Now the last step was to get the microcontroller off of the development board and on to its carrier board that would fit into the box. You can buy a carrier board, but they didn't have quite what I was looking for. Instead, I decided to build my own.

Fortunately, there is a very active forum on Basic Stamps that was able to check over my circuit diagram and make sure everything was correct. There was one mistake that they corrected, but other than that I was good to go! It took quite a bit of soldering, but I was able to do it. This carrier board is mounted on the back face of the box, as you can see here.

Now that I had my components working, I just needed to put them in a box! Since I had just finished building a my first puzzle box, I was pretty confident in my ability to do this. The one tricky thing was determining how I was going to mount the switch blocks. If I mounted them permanently, it would be quite difficult to repair something if a connection broke.

Instead, I decided to glue them to pieces of plywood, and then screw these pieces of plywood to the base of my box (see photo above). This provided two benefits: I could remove a faulty switch and if the hole for the dowel on the front of the box didn't line up exactly with the hole in the block, the block would pivot slightly to line up.

It was tough to get the hole for the display the correct size. I traced around the outside of it, but was very careful not to cut the hole too big, since that would be unsightly. Instead, I ended up cutting it too small and spending almost an hour sanding it with a file until it was large enough. One of those tiny vibrating sanders would have come in handy, I think.

I designed the box so first the top would slide off, then back panel would slide off. This would make it easy for me to service the components if a connection broke or was short-circuiting (though it would be quite a puzzle figuring out exactly what was going wrong in that mess of wires!

I mounted all the components inside the box, and everything worked great! It was really fun being able to step work through the puzzle, just like I did in when I was playing with it online, except I had actual knobs! Ok, that may sound lame but it was very exciting.

The program that I wrote for the microcontroller was kind of interesting. There are a number of words that are stored in memory that make up the puzzle. Since the maximum length of these words is 14, the typical way to store them is to give each word a 14 byte chunk of space, and then you can find the location of the nth word by taking the location of the first word and adding (n-1)*14 to that location. Then you just read off the characters until you arrive at a null character, and you're done.

This would be fine, but I was trying to conserve space since a Basic Stamp has fairly limited storage space and I needed the extra space for instructions on the objective of the puzzle and the congratulations messages that are shown after you solve the puzzle. With that simple storage method, there is a lot of wasted space because most words are much less that 14 characters long.

What I ended up doing was storing the length of the word right before the word, so I could loop through the array of words until I arrived at the one that I wanted. For example, say I wanted the 4th word in a list containing "one", "two", "three", and "four". This list would be stored as "3one3two5three4four". I start off at the first location, read the first 3 then skip 3+1 memory locations ahead. I read the next 3, skip 3+1 memory locations ahead to the 5. I read the 5 then skip 5+1 memory locations ahead. Now I am on my 4th cycle through the algorithm and am seeking the 4th word, so I should be pointing the location right before where the fourth word starts. Bingo!

If that made no sense and was not at all interesting, I apologize, but I hope that those of you who have done some programming think that it is kind of cool. Basically I implemented a rudimentary linked list data structure where each element pointed to the next element. Of course, the Basic Stamp language doesn't allow me to do any object oriented abstraction, but it did save me some space versus simple array lookups.

To this date, nobody has solved this puzzle in its physical incarnation (other than me), which is somewhat unfortunate. I think a puzzle that nobody has had the joy of solving is kind of like a kite that has never flown: it hasn't reached its potential yet! I loaned it to David from Eureka Puzzles for a while, but he didn't have the time to solve it. I might consider loaning it out if you would like to give it a shot! Perhaps a temporary trade for a puzzle I'd like to try.

Here's a picture of the puzzle in a random state. You can click here for several more photos that I didn't have room to include in the blog. I hope you enjoyed this detour from mechanical puzzles into electronic puzzles. Tomorrow: how my search to find the true identity of the designer of Frand's Mind Bender led to me purchasing an interesting multi-stage mechanical puzzle.

September 19, 2009

Frand's Mind Bender (Part 1)

Here is a picture of the completed Frand's Mind Bender. This puzzle is a physical recreation of a virtual puzzle that I found on a text-based game called LambdaMOO (telnet to port 8888).

The objective is to get the display to read 'one true beautiful poem' by manipulating the knobs. Each knob can be pushed, pulled, twisted left, or twisted right. The knobs spring back into position after each operation, so it isn't like once a knob is pushed in it needs to be pulled back out before it can be pushed again.

A character named Frand (Jay Scott) created this puzzle within the MOO many years ago, so all credit for the idea goes to him. It is a tricky logic puzzle that will require several hours to solve and a systematic approach. I really enjoyed solving this puzzle when I originally found it on LambdaMOO because it had several distinct stages to the solving process, similar to the Patience Puzzle: first you need to understand the rules that govern the puzzle, then you use those rules to formulate a solution.

In this sense, it is a lot like science: you conduct little experiments and try to understand the system. Either it behaves as you would expect it to and confirm your hypothesis as to how the system works, or something different happens and you need to modify your hypothesis of how the system works to allow for this new behavior. Can you think of any other puzzles like this? In some sense, they all are to some degree.

I had always thought it would be interesting to build a physical replica of this puzzle, but unfortunately I had no knowledge of electronics or microcontrollers. I did a bit of research and found out about something called a Basic Stamp, which is a microcontroller (little electronic brain for you non-techie folks) that you can program using a fairly simple programming language. The starter kit was about $100, but I am a fairly cheap bastard: I was worried that it might not work and I would be out $100 that could have been spent on puzzles.

One day, I was visiting a friend, Greg Charvat, who is a brilliant electrical engineering PHD who works at MIT. He was showing me around his shop and I noticed he had a Basic Stamp development board lying among the clutter. I told him I was actually thinking of buying one, and asked what he thought of it. He said he actually got it for free and wasn't planning on using it, so I could have it!

Well now I had no excuse: I had my microcontroller and a development kit, now all I had to do was learn how to use them! Fortunately, there is plenty of material available for free online that walks you through the basics of learning to program a Basic Stamp. Greg also gave me some resistors and LEDs, so I practiced wiring and programming some simple projects that flashed LEDs and whatnot.

The next big hurdle was to find a display. Most displays are fairly small, but I needed one that could show a message that was potentially 44 characters long. This is far too long to show on a typical display without scrolling, so I needed to find one that would show multiple lines. In fact, since the the words that can be produced can be up to 13 characters long, I determined that I needed a display that would display four lines.

This tied into my next problem: I needed 16 inputs to control the puzzle, since there are four knobs and each one has four operations (push, pull, twist left, and twist right), but the Basic Stamp has exactly 16 dual funcion inputs/output pins! This left me with no way to output data to my display.

Fortunately, I discovered that there was a way to configure 16 switches that only requires 8 inputs: you can wire them in a matrix configuration where four of the i/o pins are the columns and four of the i/o pins are the rows (see 2x2 example on right). The 16 switches are laid out (logically) in a 4x4 grid so that when you press a switch it connects one row to one column, completing the circut. By checking regularly for this connection, you can determine exactly which switch has been pressed. It is tough to explain, so if you are confused (and prefer not to be) check out that link above because it explains it with diagrams.

Eventually I found the display of my dreams: a Matrix Orbital LK204-25-IY. It had a nice bright backlit screen, was compatible with my microcontroller, and, best of all, it was able to convert i/o from switches arranged in this matrix configuration into simple numbers that it could pass back to my microcontroller! That meant that I didn't need to worry about programming the logic that would repeatedly scan the switches to see if any were pressed. It did cost $70, but it was definitely worth it for all the features this thing has. Also, at this point I was fairly convinced that I was going to finish this project, so I was willing to suck it up and buy the display.

Stay tuned for the 2nd half of this entry tomorrow! I ran out of time tonight.

September 18, 2009

Building My First Puzzle Box

I've been looking forward to writing this post, I hope you enjoy reading it! Here is a picture of the completed box. I was going to put it at the end where it should go chronologically, but I figure it is best to lead with a nice picture.

I think it was on the forums that I first encountered a link to Bruce Viney's website of puzzle box plans. After perusing the website and looking over some of the plans, I figured that it didn't look all that hard. Many of the designs were simply cutting various sized rectangles out of plywood, so I figured how hard could that be?

I was still home for Christmas so I had access to my father's tools and plenty of time on my hands, so I went down to Michaels Arts & Crafts and picked up some 1/8" craft plywood. While some folks may have started with Matchbox or one of the simpler designs, I decided to make the 25 Move Box. I figured that it was going to be quite a bit of work either way and I might as well go all out and make something complicated.

After carefully studying the plans, I quickly realized that cutting each part individually would take me a very long time (there were a total of about 65 parts that needed to be cut), so I created an excel spreadsheet of all the pieces, which I named and sorted by size. This allowed me to see which parts were the same width so I could cut a long strip of that width and then cut out the individual pieces.

Next, I laid out all of the parts in a PowerPoint document (yes, I am an Office junkie), so I could determine how to most efficiently use my $3 piece of plywood. That might seem insane, but I'm hard-wired for efficiency for some reason. In hindsight, this step was kind of a waste of time.

If you think that is crazy, next I planned out exactly the order of the cuts that I would be making in order to minimize the number of times I had to adjust the saw fence. This resulted in the document shown below (click to enlarge). Nice, eh?

It actually worked rather well, though there was one minor glitch that I was unaware of: I didn't have a micrometer! All my measurements were with a carpenter's ruler, so I made a bunch of cuts that were close, but not quite right (I ended up buying a micrometer to check). This was largely ok, because Bruce's design is quite forgiving, but the one place where it really hurt me was on the top and bottom panels. There are five pieces on the outside face of each panel, and if they are all too short by a tiny bit, when you line them up it is short by a noticeable amount.

So back to the shop I went and recut some of the parts. The rest were close enough or too large, so I was able to sand them down to size. I did not have a belt sander, however, so I filed them all down with a nail file. This was probably the most time consuming part of the process, my hands ached and it was terribly boring. Next time I would be sure to be more careful when making the original cuts.

I used a big plastic shop organizer with drawers to sort my parts, so I didn't have to keep remeasuring them to tell the difference between the 3"x2.75" part from the 3"x2.625" part and such. On the right you can see a picture of me working on Christmas morning, gluing up some of the assemblies.

Once the pieces were the correct size, everything glued together quite quickly. It really helped that I kept the pieces well organized for this step. I was careful to lay everything out first before I glued anything up and double checked the plans to make sure I was positioning things right. Fortunately, the gluing did not need to be super-precise, but I did my best.

Once I got all the panels glued up, I put the box together without glueing on the front panel to test it out (as Bruce suggests). When I stepped through the move sequence, it turned out that it was possible to complete the puzzle in fewer than 25 moves, since the left hand panel slid off prematurely. I ran through it a few times, double checked the plans, and confirmed that it was indeed a problem with the plans.

I emailed Bruce about the issue and he discovered that the plans on his site were out of date: somebody else had spotted the problem and he had a solution but it wasn't posted. Fortunately, the solution was very simple: I just needed to glue a stopper block on the left panel to keep it from sliding off and I was back in business!

It took a bit more sanding to get the mechanism working smoothly, but eventually I got it working to my satisfaction and was ready to finish the box. As Bruce suggested, I painted the edges black and printed out the nice orange and brown pattern that he used. I printed it out on glossy paper, cut it out, and then glued it on to the various panels using a spray glue. This may seem horrible to those of you who like to appreciate the grain of the wood, but I was using plywood so there wasn't much to appreciate.

It was tricky to cut the siders free after I glued the pattern over them. My razor kept going askew, so I had to pull them off, re-print the pattern and try again, which was quite frustrating. Eventually I got it right, though and waited for the glue to dry. Finally, I added a few coats of varnish and was ready to glue the box together.

This made me nervous, because once it was glued up I couldn't make any more tweaks to the bottom panel mechanism, but it seemed like everything worked fine so I went for it. After several hours, I tried to open the box and when I got to the bottom panel, it wouldn't budge! All this work and I had ruined it on the last step! I freaked out and pulled on it as hard as I could and eventually in broke free. Whew! That was a close one!

So that is the story of the first box that I made (I say that like I've made a ton since then...I've only made 3 more). It turned out quite well, for a first effort, I think. If I were to do it over again, I think I could get much better tolerances on the cuts by using a micrometer for everything. The end panels ended up a bit loose because they didn't fit snugly against the runners, but everything still works fine.

I had a great time showing it around to family and friends, it is a challenging puzzle but a determined non-puzzler can usually figure it out in 20-30 minutes. My thanks to Bruce for making these wonderful plans available. At the time that I made this box they were free, but now he charges a modest fee of £2 each, which I think is completely reasonable. Some of the simpler plans are still free which is great.

Well, that was a long post, but I hope you enjoyed it! Check out more pictures here. Tomorrow, I will write about another puzzle project I worked on concurrently with this one: Frand's Mind Bender!

September 17, 2009

Cast Nutcase and Cast Baroq

The day after Christmas, I headed down to Rhode Island with my parents to meet up with my Aunt and Uncle and their two children.  This is something of a tradition for our two families: rather than shipping gifts we just bring them down, go sledding, have dinner, and exchange gifts.

I received two Hanayama puzzles, Cast Nutcase and Cast Baroq. Cast Nutcase is a puzzle designed by Oskar van Deventer: a lot of his work has made it into Hanayama's product line. It consists of two nuts that rotate around a 'bolt' that has a head on each end. Since there is a head on each end, of course, you can't twist the bolts all the way off.

After playing with it for a bit, I found it fairly easy to understand how the puzzle would eventually come apart. The big challenge, however, is figuring out exactly how to implement the solution. At least with my approach, I found that there was a lot of trial and error. Sorry for being so general, but I don't want to give away too much for those of you who may want to give it a try.

Eventually I solved this one while driving home in the dark later that evening, I think it took a little under an hour (no, I wasn't the one driving). That reminds me: there is a small nut inside which is released once you open the puzzle that I lost in the car. I'll have to look for it next time I am home. I suppose you could classify this is a puzzle box since there is some storage space in the middle.

Cast Baroq, designed by Akio Yamamoto is probably one of my favorite puzzles so far. It is quite elegantly designed with beautiful curves and a nice finish. The way the pieces move is quite graceful. The following description from the box captures it quite well:

"This Akio Yamamoto creation consists of two pieces fashioned after the image of intertwining Bach melodies. Following the dynamic build up is an inspirational finale when the two pieces elegantly release from each other."
The actual solution is quite nice: there are quite a few moves required to arrive at it, but it all seems fairly logical (at least for this type of puzzle). The coup de grace is a fabulous move at the end which really was quite a treat. I would highly recommend this one! The only downside is that a slight amount of force is required on one move. This may vary with your particular puzzle, however, as is indicated in the comments at PuzzleMaster. I think that the difficulty rating of 4/6 on this one is appropriate.

In tomorrows post, I'll talk about my experience building one of Bruce Viney's excellent designs: the 25 Move Puzzle Box.

September 16, 2009

My Puzzle Nemisis and a Puzzle Cornucopia

Before heading up to my parents' house for Christmas, I decided to drop by Eureka one more time to pick up another puzzle to keep me busy over the break. I was fortunate enough to stop by when David Leschinsky, the owner of Eureka was around. I talked to him a bit about some of the Hanayama puzzles I had tried, and he pointed out a few of his favorites: Cast Chain and Cast Enigma. I already had Chain and had read about how baffling Enigma was, so I decided to steer away from that for now.

He looked around a bit and suggested The Yak Puzzle by Dick Hess. He said it was quite difficult, but I decided to give it a try anyways. It is a nice looking puzzle made by PuzzleMaster, though I'm not exactly sure why it looks like a Yak, I do believe that it does.

Well, I have spent hours upon hours with this damn thing, and it still remains unsolved to this day. I am not particularly good at disentanglement puzzles. I only have a few of them, which might be some excuse for why I had such difficulty. That said, it is quite a challenging puzzle! I hope to solve it one day: when I do you will hear my victory cry!

I spent Christmas with my family up in Beverly, MA. Thanks to a few strategically placed hints, I acquired a set of LiveCube blocks for Christmas, which was quite a treat. LiveCube really is the gift that keeps on giving, because you can build an almost infinite number of puzzles from them. The set came with some paper instructions on building a number of simple 3x3x3 assembly puzzles up through more complex pagoda shaped puzzles.

Next, I tried creating a few of the designs on Lee Krasnow's Precision Puzzlemaking Primer on I particularly enjoyed Knobbly Burr, which must be assembled in two halves that slide together (like the puzzles I made out of popsicle sticks!) Oskar's Cubes took me forever to build, but was surprisingly easy. I think it took me longer to build it than solve it. It was still an interesting design, though.

After exhausting those puzzles, I went on to build a number of the burrs described on Robert Stegmann's amazing site. I built and solved The Diabolical Structure, The Chinese Cross, The Six-Way Set, The Yamato Block, and The Piston Burr. The Piston Burr by Peter Marineau is amazing, I love the way the pieces move on it though it is quite tricky to solve. The image on the left is of a walnut version made by Jerry McFarland posted on Bill Cutler's site.

I then moved on to Ishino's awesome site: Puzzle will be played. Finding this site was like being a kid in a candy store, I could hardly decide what I wanted to try next. The one downside of LiveCube blocks is that they tend to come apart at inopportune times, so it is important to avoid designs that are too fragile.

I definitely think that anybody who has an interest in interlocking or assembly puzzles would enjoy owning a set of LiveCube blocks. I would suggest picking up at least 200, probably more, since it is nice not to have to cannibalize something you're still interested in working on to start a different puzzle. The colors seem fairly superfluous, though they are handy for certain types of puzzles where matching the pattern is important or makes the puzzle easier.

In tomorrow's post I head down to Rhode Island and come back with a few new Hanayamas. Stay tuned!