The Pentangle Puzzle

About six months ago, Kellian and I visited the Higgins Armory Museum out in Worchester, Massachusetts. After touring the museum (which is quite cool), we stopped by the gift shop. As usual, I did a quick scan around for mechanical puzzles. Much to my delight, there was a series of tubes that contained disentanglement puzzles.

It was a bit hard to tell what they were due to the tubular packaging, so I just grabbed the most difficult one which was four out of four stars labeled 'Genius' and hoped that it was something I hadn't seen. It didn't actually have a name other than "Puzzle Drum Mindgame Collections" on the packaging. This was apparently so they could keep costs down by not printing different packaging for the four different puzzles in the series.

When I got it out of the package, I realized that I had seen the design before over at Livewire Puzzles, and it was named The Pentangle Puzzle. Since it is confusing to refer to the unnamed puzzle that I actually have, I'll be referring to it as Pentangle since that name feels appropriate. To the left is a photo of the Livewire version. It is a bit hard to tell that they are the same since the photo above isn't playing up the pentagonal aspect, but they are essentially the same. I loved Livewire's description:

If you research puzzles long enough, from time to time you'll stumble upon a real gem. Where this puzzle, which we call Pentangle, originated, is not known, but we should all take our hats off to the genius who came up with it.

In solving a puzzle, most adults draw from their experience, particularly experience obtained from solving other puzzles. Furthermore, we have found that the more education you have, the more you tend to draw on skills and problem-solving techniques learned in school to help solve a puzzle. Both types of experience can be helpful, but in some instances they may divert our attention away from the area where we should be focusing. Such experience actually hinders us more that it helps us.

Experience is often powerless when faced with a lateral-thinking puzzle. Lateral-thinking puzzles are perhaps best described as puzzles in which conventional thinking breaks down. Solving such a puzzle requires a change of perspective, and the more set in your ways you are, the more difficult you will find such a puzzle.

We have had engineers, medical doctors, mathematicians and even Mensa members come back after as much as several years, convinced that Pentangle is impossible. On the other hand, we have seen many teenagers and a few tradespeople solve it in minutes, only to wonder what all the fuss was about!

I had read this a while ago and remembered the description and puzzle, which was why I was able to recognize it despite not having tried it. You can also purchase it at Puzzle Master under the name Fantastic Five, which appears quite similar (shown on the right).

As promised, this puzzle did end up being extremely difficult. I have been working on it on and off for the last six months or so. I took it on the flight to IPP 30  in Japan hoping that with enough time I would be able to crack it. Unfortunately, I did not have any success. Obviously going around the pentagon doesn't really do you any good, but if you slip the ring through one of the doubled-over pieces, you quickly become stuck.

As I mentioned in my last post, I recently solved Chain Gang, another devilishly difficult disentanglement puzzle. I realized on Saturday that I might be able to use what I learned on Chain Gang to approach Pentangle in a new light.

As I headed out the door on Saturday to Eureka Puzzles over in Brookline, I decided to throw Pentangle in my pocket and try to solve it while I was on the subway. I fumbled around with it a bit while waiting for the train, but didn't have any luck. I was just running through the same things that I had tried again previously.

Then, all of a sudden, it clicked! What had helped me solve Chain Gang was to observe a peculiarity in the design that I inferred must be related to the solution. I noticed that Pentangle also had a peculiarity that was somewhat similar, in a way. Using this, I tried something that felt new, and indeed it was! Exhilarated that I was on the right track, I quickly found the last few moves to get the ring off. Woo hoo! It is always exciting when you defeat a puzzle that has been stumping you, and I this one had been stumping me for quite a while!

The solution is pretty tricky, so I am not surprised that it took me so long to find it. I would be a bit surprised to see a novice solve it quickly as the Livewire description notes they have seen, but who knows!

I can't really speak about the differences in the design and construction of the three versions of this puzzle, but it is probably easiest to find either Pentangle or Fantastic Five rather than the version I tried. Looking at the pictures, I think that the solving experience will be fairly similar. The construction of the version that I have is fine, with a decent gauge wire and a good finish. Rather than the wood beads in Livewire and Puzzle Master versions, mine has coiled spring beads, which gave the puzzle a nice uniform silver appearance. Overall, a great puzzle that you should definitely check out if you like wire puzzles and don't mind a challenge.