This is my 14th Random Pick from My Collection.

This time, I present you the 'X Marks the Spot' puzzle. Although the original idea is around since the beginning of the 20th century, the modern version was created by Japanese puzzle designer and inventor NOB (Nobuyuki Yoshigahara), back in 1981. NOB is also responsible for the design of several Cast Puzzles for Hanayama.

You can think of the 'X Marks the Spot' as a wooden version of the Cast News puzzle. If you solved it, then you know the mechanism is exactly the same. What differentiates the two puzzles however, besides the material used, is their presentation . The Cast News is more pleasant to the eye, looking like an ancient piece of art, but the 'X Marks the Spot' looks much more intriguing and harder to come up with a solution. How can one take the X apart with that frame in the middle? - At first glance, this task seems impossible, but it's not what it looks like. The goal is simple: Take the two interlocking pieces apart and remove the square frame.

NOTE: If you don't want to know anything about the solution, don't read the italic paragraph below.

A close inspection to the puzzle will reveal that it makes a rattling sound when it's shaken. This proves that the mechanism inside has loose pieces that somehow lock the two pieces of the X together. So how do you separate it? - The answer lies in a physics principle called, the centrifugal force. After you figure how to move the loose mechanism, you just have to slide the two pieces out and remove the square frame. Solution here.


Closing Comments:

I love puzzles like this one, that have a hidden mechanism and makes you wonder for quite some time, looking as almost impossible to solve. Such a simple and easy to explain mechanism, and yet so complex that puts experienced puzzlers scratching their heads. Great for when you have friends over and see their frustration as they try to figure it out.

The 'X Marks the Spot' is available at Puzzle Master for CAD $9.95 (approx. €7).

The Revomaze Obsession is a new line of plastic puzzles, from the inventor of the metal series (Revomaze Extreme), Chris Pitt. They were launched in the beginning of 2010 and are aimed at a wider audience, mainly because of its reduced price, which is a quarter of the metal ones, and their lighter material, only a third, making them much easier to handle. All the Obsessions have the same internal maze as their metal counterparts and available right now are three levels of difficulty: blue, green and black (red was a limited edition). They also come with a very nice carry pouch.

Here for review, I have two Revomaze Obsession puzzles. One is the classic design, also used in the Extreme versions, and the other has a completely new look and sleeve design. The inside maze is exactly the same on both puzzles.

First, I'll start with the basics and with the classic design: The Revomaze is a 'Hidden Maze' or a 'Sleeve-on-Cylinder Maze' puzzle, where you have to guide the central shaft out of the internal maze. Note that, unlike the Extreme, it isn't possible to actually remove the shaft from the puzzle. You still have your certificate at the end to register your puzzle, though. The maze found on the Revomaze puzzles has all the same characteristics of a classic maze, with dead ends and traps and the harder levels will introduce you to some new unexpected features. Navigating your way through the maze, you'll often hear a click sound, meaning that you fell into one of these traps and have to guide your shaft to the beginning and start over. It's very easy and intuitive to reset the puzzle, thanks to the ingenious design that lets loose the shaft and return it to the starting position in no time.

The look and feel of the puzzle is incredible. You know you have in your hands a fantastic piece of engineering marvel, with such great care for detail and functionality. It's made of plastic, but don't let that stop you from getting one. It still feels sturdy as it is and the build quality is perfect without a flaw. The black outer sleeve has the same design lines of the Extreme, as well as a bubble badge with the puzzle's logo. Right now, all the puzzles in the plastic range are being sold only in a black color, although they were launched with the correspondent sleeve color for each different level. I would prefer if these colored versions were still available. It was a nice feature that helped distinguish them from each other like the metal ones. The shaft also has a bubble badge in each of its ends with the "R" logo in blue (different for each level), and has a great feature that helps to get a better grip on it, by having a rougher texture rather than smoother, which helps a lot after playing with the puzzle for a while...

The Revomaze is rated in difficulty at a scale of 100, with the blue being 50, the easiest one. By easiest, I mean from the three levels available. The puzzle has nothing easy about it, and requires an average of 6 hours to open. I took around 8 hours total, to finally crack the maze and I was thrilled when I could see the certificate for the first time. With my right hand and arm a bit sore from the experience, I still tried to solve it right after and only took me about a minute or so to do it again. It's amazing how I've spent all those frustrating hours trying to reach the end, and hear those clicks over and over again, just to reopen it in a matter of minutes. The maze is now printed in my memory, but it will be interesting to return to the puzzle after a while without touching it, and see if I can still solve it without falling into a forgotten trap.

One thing that you'll notice different from the metal series is that after you solve it, you can't remove the shaft completely from the sleeve. It would have been great to see that evil maze and compare it to the one I've imagined in my head. I do understand that they had to leave something exclusive for the Extremes, otherwise people would just see the difference in material and wouldn't bother spending four times more for an identical puzzle in metal. 

The New Revomaze Design

Soon to be released, is the new version of the Obsession series. The internal maze isn't changed and the shaft remains the same as the old version. The only difference is the design and appearance of the sleeve, which was completely redesigned into a nice smooth and plain surface. The sleeve is protected with a transparent plastic sheet, giving it a fantastic shiny look and now, instead of the bubble badge sticker, there's a big "R" logo with "Revomaze" and "Classic Challenge" beneath it.

The Revomaze is one of the most brilliant puzzles I've had the pleasure to solve. Its professional and pleasant outer look, alongside the addictive hidden maze challenge, makes a perfect match for an ingenious puzzle. Often described as a true test to your mental and physical capacities, the Revomaze is a tough challenge that will put your patience to the limits. When you own such a great puzzle like this, you feel like you belong to an exclusive club, perhaps too exclusive on some occasions. Since the launch of the first Extreme puzzle, there have been a few limited editions that are no longer available. It's a shame that newcomers like me, won't have a chance to own one of these rare puzzles. If you still want to try one of these unavailable limited editions, go for the Obsession - Black (3rd level), as this one is based on the Extreme Limited Edition - Black.

These two puzzles were my first experience with the Revomaze and I must say, I'm addicted. Now that I've solve the Blue Obsession, I want to try the other levels as well. I don't own a metal one right now, but that may change very soon, as I want to know how they feel compared to the plastic ones and of course, because they look much nicer on a shelf. Nevertheless, the Obsession series serve a purpose in which you can experience the sensation of playing with a Revomaze challenge for a much affordable cost... And if you're just into solving, you can get the three levels of the Obsession for less than a price of one Extreme.

It's hard to choose between the old and new design. The first has a much simpler and classier design (I love that middle bubble badge logo), and the new one has this cool and stylish look, more modern and definitely has more potential for customization. As of right now, if I had to choose between one of them, I think I'd still go with the old version, although I could change my mind when/if the custom images for the new design, become available for everyone. What about you? Which one do you prefer?

Links:

Youtube Video (solving)

Revomaze Forum (very interesting post about the history of the Revomaze)

The Lexomino Puzzle is an invention of Eric Harshbarger. It's a unique custom puzzle, made specifically for you, so what you order will be one of kind (unless you have a really common name). You can have the configuration you like, as there's no limit in the number of letters you can choose. If you wish, you can use numbers on your puzzle as well. Your goal is to pack all the letters inside the box and close the lid. Not an easy task...

The letters are all laser cut from thick acrylic, and for now, are only available in a translucent gray color. Most of the letters have a dimension of 3x5 units, although some have to be a bit bigger (R, M). It's also a nice twist to have different size letters, to make the puzzle a little more complex.

The box has a dimension of 5x5x5 units (the smallest possible for this configuration), and it's laser cut from 0.20" plywood and glued together. The name of the puzzle, your name configuration and the designer's website is engraved on the box's sliding lid. There are several box sizes available, depending on the number of letters you choose,  so check the Lexomino's website for more information on that.

Each puzzle is unique in terms of packing and solutions available. The "Gabriel M P F" puzzle has 2 unique solvable solutions and will occupy a volume of 110 voxels out of 125 (88%), for 10 letters. Each puzzle will also have its own degree of difficulty. Some might have just one solution, others just a couple, and some could have even hundreds of solutions. Ultimately, it will depend on how well your puzzle can be packed into a cubic box. Note that for some puzzles, it might not be possible to fit into a 5x5x5 box or if you choose a larger box, it could leave many empty spaces, therefore it will be better to choose one size that fits all the letters as tight as possible. Be sure to check out with Eric your puzzle configuration, box size, available solutions, etc. I tried several different configurations with him before choosing the final one, as some of them would be too easy or would leave many empty spaces.

The final version of all those failed configurations, resulted in a great puzzle with only 2 solutions, and hard ones, by the way. As of now, I only managed to find one solution and it took me about a week to solve it. The other solution appears to be completely different, because I've tried to swap just a couple of pieces around, and it wasn't possible, so plenty of replay value with this one.

Other interesting fact about the possible solutions for any given puzzle is that, no matter how many solutions it has, just one or a hundred, the level of difficulty is not directly proportional to the number of available solutions. A puzzle with a unique solution could be very hard or very easy, and a puzzle with hundreds of solutions could be hard or easy as well. It all depends on how the pieces interlock with each other.

You can buy a Lexomino Puzzle by contacting Eric at the e-mail address found in his page. Each puzzle has a base cost of $25 + $3 per letter + $10 shipping. No solution included, although the puzzle comes in its solved state inside the box. If you want a solution engraved on the box, that's another $10).

Eric also designs other types of puzzles and makes use of old CD cases in a very original way.

Suffice to say, this is now my favorite puzzle. What more could you ask for, than a puzzle made just for you? It makes you feel rather special, to know that you're probably the only person in the world that will play with this particular puzzle configuration. I urge everyone with a passion for puzzles, to get one of these... It's also a perfect present for someone that's into puzzles.

Random Pick #13 from My Collection.

The Mini Puzzlers are a range of pocket sized puzzles manufactured by Pentangle. There are 12 different challenges available and they vary in several different categories and difficulties (Assembly, Interlocking, String, etc...). Each puzzle comes in a clear plastic case, has a different colored tape for the lid opener and the writing is engraved in golden ink. No solution provided...

Here for review, I have half of them:

The instructions in this one aren't entirely clear. You have 16 diamond-shaped pieces with "clubs", "hearts" and "spades" and you're supposed to fill a grid by matching identical symbols. Since you have three of the four shapes depicted on the pieces, and the only left is "diamonds", I guess the goal is to create a large diamond with the pieces, as demonstrated in the picture below... I'm  not sure if it's possible to have other shapes as solutions, though. This is my favorite from the ones I have, because of the colorful design and overall presentation of the pieces.

Edit: Cleverwood has a more detailed description about the goal of this puzzle. You have to build a hexagon, with the blue lines on the pieces as boarders, to group together the "clubs", "hearts" and "spades". I guess it's possible to build other shapes, after all, counting the one I built...

(Click to Enlarge)

7 pieces form this variation of the Soma Cube by Piet Hein. The object of this puzzle is very similar, with the only difference that you have to arrange the pieces in a checkerboard pattern that fits into the box. From the 240 possible solutions, only a small fraction of them builds this pattern. It sounds harder, but if you think about it, it's much simpler... As there are less ways to assemble it in any given way, you're left with only a few possible moves for a specific piece and by exclusions, you'll probably find a solution faster than if it was for the regular Soma Cube.

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The classic challenge...

Now with six pieces, your goal is to find a solution to make a cube. For reasons described above, this is probably a harder challenge than the Soma-Check, as there are much more positions available for any given piece, thus providing also many impossible ones in the process... For alternate challenges, you can also build different shapes, other than the cube (a rectangle, for example, or even a 2D square with all of the pieces).

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The Pyramid, or tetrahedron is formed by four identical pieces. Each piece has a rhombus base and two pairs of identical faces. To build the triangular based pyramid, you have to only find a way to connect two pieces in a stable way (they form a square in one of their shared faces). When you identify that connection, the other two pieces connect in the exact same way. now, you just have to join those two square faces and your pyramid is built. Not that easy when you don't have any information on how to solve it.

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This is an original variation of the classic Soma Cube. The puzzle comes in the cube state solution and you have to build a penthouse with the two oblique pieces for the roof. As the puzzle is formed by a box of 4x4x4 units, and not counting the two roof pieces, you have to build a 3x4x4 rectangle and then, simply add the roof as the final step. The puzzle is described to be harder to return to the cube solution, but I actually took the same amount of time approximately, to find both solutions... It's up to you to find out which one is harder, or if they're the same difficulty.

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Another classic design of the six-piece burr. The only difference is in its size... As with almost every burr (there are a few exceptions), this one is no different when it comes to the solution. There's a "key" piece that doesn't have any inside cuts and just slides out to take all the other pieces apart... The difficult part is to put it back in the original state, though. If you don't pay close attention when you separate the pieces, it may prove extremely difficult to find the correct solution again. Only one solution, by the way...

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One curiosity from the six-piece burrs: There are 119,979 ways to build a six-piece burr from 369 different pieces.

Several of the Mini Puzzlers challenges are widely available for many years now, so why buy these? Well, if you're a collector, they are all worth getting. Mostly, for the neat way they're presented, with a reduced size and a different colored tape for each box. For more details go to Pentangle Puzzles.