One In A Trillion

This tray packing puzzle, designed by Joseph Becker came from Steve Strickland's puzzle shop and is limited to 30 copies. Measuring 130mm square and about 18mm thick (including the blocks), it is made from 8 different woods including Walnut, Rosewood, Granadillo, Bocote, Canarywood, Purpleheart, Cherry and Teak. I am not that huge a fan of wooden puzzles and one look at the puzzle and I knew it was not going to be easy. But the combination of 8 exotic woods of different colour tones was just too hard to resist. Another plus was the very reasonable price.

The tray contains 9 separate pieces, each of which is made of individual cube blocks glued together to form irregular shaped units. Several blocks come permanently affixed to the tray. Quality of the puzzle is reasonably good; with each of the cube block edges even bevelled. The only minus here is that the bottom of the tray feels like it has not been sanded smooth sufficiently or at all.

The puzzle is called One-In-A-Trillion I think, for very good reason! It really is very difficult, at least for moi! There are two objectives to this puzzle. One, which is the easier (not easy) of the two is to fit all the 9 pieces back into the tray, and here there are two ways of doing it, according to Steve. I was "fortunate" to receive the puzzled sealed in plastic in the solved state...this gave me a chance to have a really good look at the puzzle pieces. Two caught my attention; one was the Purpleheart (so purple you just can't miss it!) and the other was a very light coloured wood. Luckily I was able to roughly recall where their positions were in the tray. Hence, it was now a lot easier as I had only 6 pieces left to deal with, since one of the pieces, a straight 4-block unit already has a pre-determined slot in the tray.

Through trial and error, I managed to put the rest of the pieces into position, but then, it still took me a very long while to complete. Let's face it, if all the pieces had been made of the same coloured wood, I seriously doubt I could have solved it. Perhaps that was why the puzzle has been made the way it is...otherwise it would have been too difficult??

The second objective is to use the 9 pieces to form a 4x4x4 cube. This one really got me super-stumped! I spent several days trying all sorts of configurations but got no where. Not wanting to frustrate myself any further, I checked out the solution. Even this was no walk in the park and I knew I would never have been able to solve it without the solution. I also found out that only 8 pieces out of the 9 were required! I think BurrTools might probably do the trick here, but I haven't learnt how to use the software yet!

For those that enjoy packing or 3D assembly puzzles with loads of challenge, I think the One-In-A-Trillion is really excellent for being able to combine two puzzles in one, not to mention that it is very good value for money too, effectively two for the price of one! An added bonus is the different exotic woods used which makes the puzzle aesthetically pleasing and exude quality, especially with the 4x4x4 cube. Definitely worth acquiring.

Kuku

Update 24 October 2017 - Dear Reader, please check out my new puzzle blog and e-store at http://mechanical-puzzles.com

The Kuku has been sold by Sonic Games in the UK for quite a while already, since 2009. Measuring a rather small 40mm in diameter, it comprises three symmetrical pieces which interlock together to form a sphere. The three pieces are coloured polished aluminium, anodised blue and gold. There have been some criticism in cyberspace levied on the Kuku as to the quality of manufacture. (see Neil's review on his puzzle blog). I suppose this is not entirely surprising since Sonic Games' earlier puzzle the Isis, at one time touted as the "hardest puzzle in the world" also received a plethora of negative comments over quality issues.

Although I hesitated at first, I was interested to see for myself the Kuku's puzzle mechanism. So I finally bought one after Sonic Games offered a special website price discount. Thankfully my copy did not appear to have quality issues and overall fit and finish is of a very high standard.

The object of the puzzle is to unlock the three pieces and remove a small plastic token with an imprinted number. Kuku owners, once they solve the puzzle, can register this number on the related Kuku website, play a game and stand to win a prize. According to both Neil and Jonas Bengtsson in his blog, there are apparently two versions, medium and hard; but I do not know which my copy is, the medium or the hard.

When I first examined the puzzle, I had a pretty good idea how the three interlocking pieces were held together. A number of other metal puzzles in the same genre, several of which have been reviewed on this blog, apply a similar principle to that of the Kuku. Gravity plays an important part. The difficulty of the Kuku perhaps stems from the fact that all three interlocking pieces forming the sphere are symmetrical, so trying to determine the orientation of the puzzle vis-a-vis how gravity applies makes it very challenging indeed. Like the Purple Isis I wrote about earlier in this blog, I had no intention of spending a lot of time on the Kuku. Checking out the internet and help videos on YouTube, I was able to take apart the Kuku quite quickly. I will not go into any "spoiler" details here since there may be readers here who are determined to solve the Kuku on their own. But looking at the internal mechanism, this one is not easy to solve repeatedly.

For the design and engineering that goes into the manufacture of a Kuku and from both the puzzle aspect and price point (and just so long as there are no quality issues), I would say the Kuku is certainly worth acquiring.

Zauberflote

I was fortunate to get my hands on the Zauberflote a while back from Eric Fuller/Cubicdissections. It was their last piece available for sale. This little puzzle designed by Gregory Benedetti, is diminutive in size (measuring 55mm x 40mm x 22mm) but don't let its small size fool you! This one is tough! The puzzle consists of two flat panels of acrylic with different shaped cut-outs and  four different size/shaped blocks of Yellowheart wood. Although it does not look like one, the Zauberflote is classified as a burr puzzle. The object is to fit the four wooden blocks from the largest to smallest (left to right) into the cut-outs of the two acrylic panels to form an assembled unit. This requires manipulation and movement of both the Yellowheart blocks and the two acrylic slabs, similar to how one would go about solving a traditional burr.

Quality is very high for this puzzle; both the Yellowheart blocks and acrylic pieces are very precisely cut and fit and finish is excellent. Even though the blocks may be small and even look a bit fragile, there is no fear of breaking them since Yellowheart is a really tough and durable hardwood with a Janka hardness rating even higher than Mahogany and Maple. My only gripe (no fault of Eric's) is that in Singapore where humidity is very high, the Yellowheart blocks tend to expand, making their fit very much tighter than it should be. But an overnight stay in my camera dry-box at a No. 45 setting took care of the problem quite easily.

Prior to attempting the puzzle, I had already read reviews of the Zauberflote by 4 other very experienced puzzlers, Neil, Allard, Kevin and Brian and from what I gathered, I knew I would not have an easy time with this puzzle. There were comments about using BurrTools, rotation of the pieces and more than one way of solving the Zauberflote. But the general consensus was that this little bugger is very challenging. True enough after getting the first 3 blocks into the acrylic slabs, I was stuck with the 4th block...and stuck for a really long time. No amount of sliding or rotating helped.

Generally for most of my puzzles, I would go for the solution (or help) if I find I am getting nowhere after some time, usually not very long...ha ha (PS - there are other equally or more important things in my life apart from puzzling!). But in the case of the Zauberflote, for some reason, I actually stuck with it for quite a number of days. In fact I think it was ego that drove me on - I did not want to admit defeat to such a tiny puzzle. But alas, after almost a week of frustration, I finally threw in the towel. Since the puzzle did not come with a solution, I decided to seek the help of fellow puzzler Kevin Sadler of PuzzleMad.

Kevin was kind enough to email me some clues but also offered to send the solution on a BurrTools PDF should the clues be insufficient. I looked at his clues and realised that I had one crucial one step wrong, hence my inability to assemble the blocks correctly. After I corrected my misstep, I pretty quickly managed to solve the Zauberflote using the rotation method. And after a couple of practice runs, I was able to solve and unsolve the puzzle quite easily.

Tiny and cute though it might be, the Zauberflote packs a real wallop! It is very challenging, compounded by the fact that its small size and small pieces make it even harder and at times quite fiddly to handle. Not really suitable for those with very large hands and fingers. But for the very reasonable price of $20 and given its quality and level of challenge, it is excellent value for money. If you come across one available, don't hesitate to buy it!

Aluminium Hedgehog In Cage

The Aluminium Hedgehog puzzle is in the same genre of puzzles including the Hanayama Cast Cage and Man The Torpedo. All three puzzles are similar in that they require you to remove an object from the puzzle "cage". In the case of the Hedgehog, the object to be removed from its cage is a hedgehog represented by a sphere with 10 rods of varying lengths inserted into it.

My copy of the puzzle came from William Strijbos and is entirely made of polished aluminium, both the cage as well as the hedgehog. Quality is very good and even the insides of the cage is pretty well finished with virtually no rough edges. The puzzle measures about 70mm tall with a diameter of 50mm. The cage is made from five openings cut into an aluminium cylinder covered at the top and bottom. The size of this puzzle is really nice since it is large enough for the hands to hold it comfortably and I had little problems gripping the hedgehog.

I did not find the puzzle difficult after my previous experience with the Cast Cage and I removed the hedgehog within a couple of minutes. This is not to say that the puzzle is easy; by no means is it so and for the uninitiated handling a puzzle like that for the first time, it may take quite a while to solve it, as was proven by a non-puzzling relative of mine who dropped by for a visit. He was fiddling with it the whole evening and still couldn't solve it by the time he left. (PS-If you need a clue on how to go about getting the hedgehog out, please see my review of the Cast Cage).

Overall this is a fun puzzle which can be solved very quickly and repeatedly once you figure out the initial solution. With its nice shiny polished exterior and relatively large dimensions, it also makes an interesting conversation piece.

La Cerradura Doble

This puzzle, which was an entry for IPP28 in 2008, was acquired from Robrecht Louage, who was this year's IPP 31 Grand Jury Prize winner for his 4 Steps Visible Lock reviewed some time back in this blog. Cerradura in Spanish means "lock" and one look at the puzzle and you probably can tell why.

The Cerradura measures 160mm(L) x 95mm(W) x 16mm(H). Made of Corian (the type of material found in kitchen counter tops), steel and acrylic, the puzzle is not only hefty but also very well constructed and finished to tight tolerances. All moving parts slide and move as they should. The overall combination of the three different materials and contrasting colour tones gives the puzzle a very solid and industrial kind of look.

The puzzle consist of two flat steel plates or "keys" that are "locked" in place by 5 movable sliders with grooves or "teeth", each of which can be pushed either up or down within a narrow range of movement. Covering this assembly is a acrylic top plate screwed into position at the corners.

The object of the puzzle is to remove both steel keys from the puzzle. To do this, you have to navigate each of the steel keys out of the puzzle by moving the sliders individually to free the steel keys in order for them to pass through. This puzzle has been designed in such a way that you cannot remove one key entirely and then followed by the other. Both keys need to be worked on and moved in tandem. Occasionally you will also need to move one key backwards in order for a slider to disengage the other key for the latter to move.

This is not a very difficult puzzle and I was able to remove both keys after about 40 minutes of pushing, pulling and sliding. As usual I applied my trial and error method which did the trick quite well here for this particular puzzle. The Cerradura is one of those puzzles that not only can you see exactly what you are doing and what you need to do next, but you also remain constantly aware of the progress you are making as you slowly manipulate the two keys out to reach your goal.

Returning the puzzle back to the original state required almost the same effort as removing the keys but somehow I felt the reverse was slightly easier to carry out. Overall, a nice puzzle that is sufficiently challenging not just for the enthusiast; but with everything in full view (without hidden magnets, pins, mazes etc), can quite easily accommodate non-puzzlers as well.

For another take on the La Cerradura Doble, check out Allard's review on his puzzle blog.

Cat & Dog Sliding Puzzle

This sliding puzzle comes from Dutch collector and puzzle designer Ton Delsing. Ton's area of interest in particular are sliding puzzles and he also designs his own sliding puzzles for sale and exchange. Ton's Horrible Hexagon was one of the design entries of IPP 31 in Berlin this year. I had first come upon the Cat & Dog featured in Geduldspiele's website where it was described as "one of Delsing's best puzzles...". My only previous encounter with sliding puzzles was some years ago with the 15 puzzle and more recently, making my own Lego version posted earlier in this blog. With my limited experience, I decided to have a go at the Cat & Dog. I happened to have a puzzle that Ton wanted and eventually exchanged mine with one of his.

The Cat & Dog measures 116mm x 92mm x 18mm and is formed by a number of wood layers glued together. The frame and sliding tiles are cut by LaserExact!. Overall construction, fit and finish is very good. The object of the puzzle is to rearrange the tiles in the unsolved state (as in the photo above) to one of two finishes printed on the back of the puzzle (as in the photo below).

Unlike the traditional 15 type sliding puzzle where all the pieces can slide in various directions, the difficulty level of the Cat & Dog is significantly increased by the restricted movement of the upper middle blank tile in the centre; which can only move either up or down one position. This severely curtails the movement of all the other tiles, especially since horizontal movement along the centre is no longer possible. If both the upper and lower blank tiles are not moved, the rest of the tiles can only move within the frame in a circular fashion and there would be no way to rearrange the order or position of the lettered tiles. Thankfully, the lower blank tile is movable along with the rest of the lettered tiles and this frees up "more space" for repositioning of the lettered tiles.

I started off with much gusto! But after nearly half a day of continuous trying, I still ended up with at least two tiles in the wrong position. This puzzle can literally make you go round in circles! I emailed Ton for some assistance but unfortunately even with his hints, I could not achieve Finish No.1. I spent another day or so sliding but still got nowhere.  A second email from me saw Ton send me a detailed solution. The solution looks rather complicated and would require I think, some time for me to properly digest. My only consolation is that Ton did say the solutions to his sliding designs are not easy...yes, I fully agree! I have decided to put away the Cat & Dog for the moment and come back to it another day. Probably its my lack of experience, but this is one heck of a tough cookie!

Tricky Dick

I am not a fan of entanglement puzzles but this rather interesting (and inexpensive) one with a strange name caught my eye when I was at the Yallingup Maze in Western Australia. The Tricky Dick was designed by Rick Eason and presented at the 19th IPP in London in 1999. The copy which I bought was made by Mr Puzzle Australia.

The puzzle consists of three wooden pieces (looks like stained radiata wood), namely an octagonal block attached by a rope to a long cylindrical rod. The rope which runs through the centre of the rod is sealed into the rod. A circular disk is attached to the end of the rope. Overall the construction and quality is good. A brass ring encircles the rope and the object of the puzzle is to remove this ring.

This is my first entanglement puzzle and my attempts to remove the ring initially ended with the brass ring and the wooden pieces all tangled up in a twisted mess. I suppose there is a reason why these puzzles are called entanglement puzzles. Now I had two objectives...one, to disentangle the knotted mess and two, to solve the puzzle by removing the ring.

After over an hour or so, I finally managed to untangle the puzzle back to its original unsolved state. This actually gave me the "A-ha" feeling and I was pleased with myself for achieving the disentanglement. However, I didn't want to put myself through another hour of frustration, so I decided to check out the solution that accompanied the puzzle. I found the solution not exactly easy to follow but it was better than none. This is a tough puzzle. I would never have been able to solve the puzzle without the solution. Following each step to the tee, eventually I got the brass ring out!

The Tricky Dick is rated at a difficulty level of 8 out of 10, so I am not surprise that I didn't even come close to solving it. Honestly, even with the solution which shows the sequential steps, I still cannot quite comprehend and figure out how the brass ring is removed from the rope-wood ensemble, given that it looks really physically impossible to do so. Anyway, for entanglement puzzle enthusiasts, here is one challenging puzzle to consider.

Rick Eason has a website which features two variations of the puzzle and hints to solving. Tharn Jaggar's puzzle blog also has nice photos of the step by step solution.

Four To Square

The Four To Square is a 4-piece 2D packing puzzle designed and made by Jacques Haubrich. This puzzle was entered into the 2011 IPP Competition in Berlin. Made of stainless steel, the puzzle is 73mm square in size. Overall quality and construction is very good and the 4 irregular shaped pieces are of a slightly different colour tone from the tray giving the puzzle a nice contrast. The object is to pack the 4 pieces flat into the tray.

While it might look deceptively simple with just 4 pieces, which is what I had (wrongly) thought initially, the puzzle is actually much harder than it appears. I actually spent quite a bit of time on this puzzle over a number of days, yet I just could not fit in the last piece nicely into the tray. For a while, I even wondered if Jacques had sent me the wrong pieces as he was packing his puzzle off to me or the pieces of my copy were not cut that precisely! Well, thankfully it was neither. Truth be told, after much trying and not getting anywhere with this, I emailed Jacques for a clue. He was kind enough to send me a drawing with one of the pieces in the right position within the tray. Even with his clue, I still took a bit of time to finally get the remaining 3 pieces nicely inside the tray. I was just not thinking out of the tray (or box) and trying to fit the pieces from just one angle!

Overall, a nice little (no pun intended) challenging packing puzzle.

Aluminium 10 Move Burr

I acquired this handsome 6 piece burr from William Strijbos. While the puzzle was made by Wil, the design of the burr actually came from Peter Marineau and the original name of the burr was "Piston Puzzle". As the name implies, you need to make 10 moves to remove the 1st piece, although the Piston Puzzle is a 9.3 burr (ie 9 moves to remove the 1st piece).

The quality of this burr is excellent. Made of solid aluminium, every one of the 6 pieces of the burr is very well CNC milled and finished to very tight tolerances. All the pieces fit nicely together and are able to slide smoothly against one another. This is not something you should allow a young child to handle; while the edges are sharp, they won't cut. However, the corners are really extremely sharp and if you ever dropped this thing on your bare thigh or foot while puzzling, and one of the corners happens to land on your flesh, a nasty bleeding cut is almost guaranteed! The puzzle itself is about the right size for the hands, measuring about 67mm x 67mm x 67mm.

The 10-move has only one solution - meaning you have to engage the right pieces with moves in the correct sequence in order to solve the burr. I found the disassembly not too difficult; about 15 to 20 minutes of pulling and pushing various movable pieces here and there was all it took for me to take apart the 6 pieces. But when it came to fixing everything back together again, this was where I was stumped! And super-stumped for a long time. On hindsight I should have "recorded" or noted down my disassembly moves but was too lazy and impatient to do so, hence I paid the price. Something I will definitely do next time with the next burr.

For over several days, I tried fitting all manner of configurations and moves with this burr but got no where. I just couldn't put Humpty Dumpty Burr back together again. I don't have much experience with burrs, having only gone through several relatively easy ones, so I found this one extremely tough! Eventually I decided not to frustrate myself any further. As Wil does not accompany his puzzles with solutions, I tried checking on the internet. I had heard about the BurrTools programme from some of the other puzzle bloggers, but after a quick inspection on the BurrTools site, decided it was too complicated for me and so gave it a pass.

The solution I finally found came from the IBM Research Burr Puzzles site where there is a Java applet showing the sequence of steps necessary to disassemble the Piston Puzzle. For those interested, other well known and popular burrs by designers such as Stewart Coffin and Bill Cutler are also featured. All I did was to go in "reverse" and the programme showed me how to reassemble the puzzle step by step.

Following the applet, I was able to put the burr back together again, much to my relief, as I really did not want to put away 6 loose pieces back onto the shelf unsolved. I found this burr too much of a tough cookie for me (maybe I should have gotten Wil's 7-move burr to start off instead) but nonetheless glad that I got it for my collection.

For other comments on the 10-move (and 7-move) burrs, do look at Oli's, Neil's and Allard's puzzle blogs.

Cross

The Cross was designed by William Strijbos in the 1970s and according to Wil, was his first puzzle. Like all of Wil's metal puzzles, the Cross is very well constructed to tight tolerances and of excellent quality. Measuring 60mm x 60mm x 35mm, the puzzle is made of solid aluminium. While not that large, the Cross is feels weighty in the palm.

The puzzle consist of two blocks interlocking with each other to form a "cross". Inserted within each of the blocks is a metal rod which locks the two blocks together. The object of the puzzle is to separate the two blocks by amongst other things, manipulating the two metal rods, which can rotate on its own axis and slide in and out in both directions.

I had the benefit of reading Kevin's review of the Cross prior to getting the puzzle, hence I had a reasonably good idea how the puzzle worked. Despite this, I still took about 45 minutes to figure out how to remove one of the rods which is the first of several steps to the eventual separation of the blocks. If I had not read Kevin's review, I think I would have taken at least a couple more hours.

Once disassembled, I took nearly another 30 minutes to put everything back together; this was just as hard, if not harder than the taking apart. I got stuck a few times before both rods were finally inserted flush into their respective holes and locked the puzzle. No banging or knocking is required here as there are no magnets, however you do need to make good use of gravity to solve the Cross.

After I had taken apart the Cross, I studied the internals carefully to determine the sequence of disassembly and reassembly, even marking a couple of the parts with little coloured stickers to help me remember the orientation of the puzzle and what goes where and which direction. There is a series of moves in the correct order which must be adhered to. I must say the way the puzzle is taken apart and put together is very clever; really amazing for a first puzzle design from Wil or for that matter, anyone else. After several practice runs, I eventually got the hang of it and managed to solve the Cross repeatedly and fairly easily.

This is a nice take-apart type puzzle to own. While not extremely difficult; it poses a substantial challenge for the mind and for the hands. The number of moves required (and in the right sequence) to disassemble and assemble it keeps the puzzle sufficiently engaging for repeated play. There are three other reviews of the Cross you may wish to check out. (see Jeff's, Neil's & Allard's puzzle blogs).

Cast Spiral

This puzzle was acquired at the Yallingup Maze, Western Australia not by me but by my brother-in-law. Being a first time puzzler, he didn't dare to risk spending a lot of money on a puzzle and hence decided to try out a relatively inexpensive item. The Cast Spiral by Hanayama, in all its shiny metal looked appealing and good value-for-money to him. I was going to buy the Cast Cage so it was also in my interest that he got something different in order that I could try his puzzle as well :-)

The Cast Spiral is made of aluminium and measures about 48mm in diameter with a thickness at the centre of approximately 20mm. It is made up of 5 solid interlocking pieces which can be "stretched" out like a spiral. For its size, the Spiral feels pretty heavy in the palm.

The object of the puzzle is to disengage and take apart the 5 individual pieces. When its fully stretched out, the Spiral's 5 pieces remain locked together, and there appears to be no possible way to unlock them. Both of us took turns at trying to solve the Spiral and for the time we spent at the Maze Cafe, neither of us could solve it.

However our joint efforts came to fruition later in the evening when we were waiting for our food at the take-out restaurant; my brother-in-law managed to take apart the 5 pieces! Not bad for a first-timer! He did admit it was more by chance than anything else that he managed to fiddle it apart. He continued to play with the 5 separate pieces for a while but this time, couldn't get it to lock back together. This is where I managed to redeem myself - I took the puzzle away from him, studied it for a while, tried to determine which piece linked with which and thankfully, after some trying, managed to fit the 5 pieces back to the solved state.

After the puzzle had been solved, we slowly retraced the steps to determine the correct way to disassemble and assemble. Once we figured out what were the moves, it was pretty easy thereafter to take it apart and solve it repeatedly. Overall a fun puzzle that can be easily taken anywhere. Three other bloggers have also written about the Spiral so you may wish to check out Oli's, Kevin's and Brian's puzzle blogs.

Just Six

This 6 block burr puzzle was acquired from the Yallingup Maze as in my previous post on The Cube. Again it is made by Mr Puzzle Australia of cedar stained radiata wood. Externally, this puzzle seems to be similar to the Sly Burr on the Mr Puzzle Australia site and the wood there used by the Sly Burr is different. This is where any similarity ends; Allard has commented "the Sly Burr really lives up to its name" (Allard, thanks!). The package description states that this puzzle was sold as the The Small Devil's Hoof in its earlier incarnations. It is a fairly large burr of around  90mm square. The puzzle was actually available in either sharp edged or bevel edged and I chose the latter. Again, overall quality is very good here.

The object of the puzzle is to assemble the 6 blocks (all differently cut) into one interlocking burr. None of the 6 blocks are identical while 1 is a solid piece which locks the puzzle together.

There is obviously a sequential way to assemble the burr but I proceeded with my usual trial and error style. I was actually able to solve this burr within a matter of minutes even though this puzzle has a difficulty rating of 7/10; surprise surprise!! After solving it, I took a look at the solution and true enough, the steps were laid out in a particular order. Personally I think the puzzle is not so complicated that one cannot solve it by trying different interlocking configurations to see which works since its only 6 pieces and the relatively large size of the blocks allows for easy handling. After my earlier struggle with The Cube, this puzzle provided some welcome consolation! Allard has also written about the Just Six so you may want to check out his comments on it.

The Cube

This 3D packing puzzle is designed by Andreas Rover and made/sold by Mr Puzzle Australia. I bought it while on holiday visiting the Yallingup Maze in Western Australia. The Cube was also an IPP27 Gold Coast, Australia exchange puzzle.

The Cube is made of cedar stained radiata wood and has an orange brown colour. It measures 90mm x 90mm x 45mm (with 6 different shaped blocks inside the box frame). Construction, quality of fit and finish of the box and individual blocks are very good. The object of the puzzle (apart from merely taking out the blocks and fitting them all back nicely) is to make use of the loose blocks to form a cube.

The blocks are all of varying shapes and while I expected the task of solving to be not that easy, I did not expect that I would struggle for so long and still not be able to form the cube as required. After nearly several hours of trying, I gave up and decided that there must be something I was not doing right and went for the solution. What I saw stumped me! I totally did not expect the solution as that which came with the puzzle. I looked back at the description of the packaging which reads: "The object of the puzzle is to make a cube with the given pieces. Not your usual 3x3 cube; a very entertaining puzzle"; I then realised that I had overlooked a simple but vital clue in the said description.

The Cube is rated at level 5/10 difficulty level but I would say it is closer to perhaps 6. While not overly difficult (on hindsight), it is certainly had me fooled!

P&L Packing Puzzle

The P&L was designed by Junichi Yananose and made and sold by Mr Puzzle Australia (aka Brian Young) for exchange at IPP31. It is actually a petite packing puzzle measuring 80mm(L) x 63mm(W) x 23mm(H) and very pocketable. Again the attraction for me to this puzzle was the use of 5 different woods consisting of Queensland Silly Oak, Tasmanian Blackwood, Pepperwood, Rosewood and Queensland Silver Ash. My copy is very well cut and made and all the pieces fit into the box very nicely.

The object of the puzzle is to pack into the box 5 L-shaped pieces and 5 P-shaped pieces. One of the L-shaped pieces has a No.31 (IPP31) on one of its surfaces and this No.31 must show up on top when the puzzle is in the solved state. The 10 pieces form two layers inside the box with no empty spaces. Externally, it looks like the box has got extra thick sides and an unduly small space for the pieces, but this is because the opening of the box leads to a much larger hollow inside the box to which all the pieces must fit in.

The P&L in my opinion poses a reasonably fair challenge. Just when I thought I was about to be able to fit every single piece into the box, I find that I can't fit that one last piece; and out comes all the Ps and Ls again. It took me a couple of hours of trying different layout configurations within the small confines of the box before I finally slotted in the last P on top. Overall, a nice and cute little packing puzzle but those with large hands and fingers may find the small pieces a bit fiddly and clumsy to handle.

Six Pack

This 6 piece interlocking burr puzzle was designed by Jim Gooch and made by Steve Strickland and presented as an exchange puzzle at IPP23 in Chicago in 2003. I was particularly attracted to this puzzle because it is made from 6 different types of exotic hardwoods namely Bubinga, Red Oak, Paduak, Mahogany, Walnut and Pecan. The copy I acquired is apparently from the original batch that was made for the IPP23 exchange.

The puzzle measures a comfortable-for-the-hands 62mm square. Quality of my copy as well as the cut, fit and finish is very good. The 6 pieces move smoothly against each other with no jamming, even after several weeks in the sort of humid weather in Singapore.

While the puzzle is not very difficult, it was also no walk in the park either (for me). It took me a quite a while to study the right moves and try remember the sequential steps needed to put the puzzle back together after taking it apart. What is of help here is the 6 different woods of varying colours which act as visual cues in remembering the correct steps. If the puzzle had been made entirely of just one type of wood, I think it would have been a lot harder.

Overall I think its a nice puzzle which doesn't require a lot of time (nor a lot of moves) to solve...unlike the stories I have read of puzzles that really test the patience which require moves that can run into the hundreds to solve.

Tresor

This mini safe box puzzle came from Geduldspiele's site under his Exchange section. Tresor means "treasure" and I guess the name is quite suitable for this puzzle. I had first seen the Tresor reviewed on Jeff's blog and decided it was too unusual to miss owning one. Designed by Clause Fohlmeister and made in Germany of quite sturdy plastic, the safe measures 4 3/4in(H) x 3 1/2in(W) x 2 3/4in(D).

Externally, it looks like the miniature of a typical safe with a red coloured combination dial, a keyhole and a four-spoked turn-wheel contrasted against the white colour of the box. At the back there is a slit, presumably for depositing coins for saving. A plastic colour matching red key also comes with the puzzle. The objective of the puzzle is to open the safe door.

For the first couple of minutes, I was fiddling around with the combination dial and turn-wheel and also twisting the key to see if these could get  the door open. Nothing seemed to work at first. I must admit that when I did finally open the safe door, it was really by pure chance. The locking mechanism of the door is quite clever and I would probably have taken much longer to figure out the solution if not for my stroke of luck.

I thought the Tresor was fun, no matter that I found the solution by chance. Besides being a puzzle, it also serves the very useful function of a piggy bank. Will probably pass it on to my son when he is old enough to learn the importance of saving.

Self-Made Lego Sliding Puzzle

A while back, I chanced upon several YouTube video clips which showed sliding puzzles made out of Lego bricks. One video in particular, by someone named "Mahj" gave pretty good instructions with Flickr photos of how to go about building one. This caught my interest and I thought a Lego puzzle was something interesting (and relatively easy) for me to build on my own.

After some research on the internet, I discovered Bricklink was THE place for getting Lego bricks, whatever the quantity, colour, type or size. Bricklink is a site which consists of an aggregation of over 5,400 Lego brick sellers from all over the world, somewhat similar to Ebay stores. If you can't find what you want on Bricklink, it probably doesn't exist! The seller from which I got all my little bricks and parts from is aptly known as Missing Bricks based in the USA. I selected the required number and type of bricks needed and duly placed my online order. Some of the colours were not available so I had to make do with what I could get. My package of Lego bricks promptly arrived at my home about a week and a half later.

Using Mahj's photos as a step by step guide, I actually managed to constructed a pretty nice looking puzzle for myself (if I may say so). Instead of numbers in the traditional 15 Puzzle, I decided to use alphabets and created a sentence on the sliding tiles. Below is my own homemade Lego sliding puzzle from start to finish.

Photo 1: All the bricks laid out and ready for assembly

Photo 2: Building the base

Photo 3: Adding the structure for the sliding tiles

Photo 4: Completing the structure for the sliding tiles

Photo 5: Adding the smooth surfaced red sliding tiles

Photo 6: Completion of the red sliding tiles leaving one
tile empty. Making sure all the tiles slide smoothly

Photo 7: Alphabet stickers; effective and inexpensive
For those with large hands, use a pair of tweezers

Photo 8: Pasting the alphabets on the red tiles and
putting everything together 

Photo 9: Completed Lego Sliding Puzzle 

Cast Cage

Like the 12 Points To Insanity reviewed earlier, I got this Cast Cage from Yallingup Maze. Made by Hanayama, the puzzle is about  2 1/2in tall and 1 1/2in in diameter. It consists of a black coloured cage made of steel I think, and contained inside is a 6-pointed asymmetrical star made of aluminium. Construction is reasonably good although the fit and finish of the two halves forming the cage could have been better. The object of the puzzle is to remove the star from one of 4 irregularly shaped "cut-outs" around the sides of the cage.

While it looks easy on the outside, it really isn't. The trick is to figure out which of the cut-outs the star can be removed from. I must admit that I solved this puzzle through trial and error; well I suppose then again quite a lot of puzzles of this genre are solved this way anyway. After quite some time trying all the 4 cut-outs, I managed to get the star more than half way out through one of the cut-outs (by chance really) and figured that probably is the correct one. And I was right; with a bit more manipulation, the star practically fell out.

What was more amazing was how easy it was to slip the star back into cage through the cut-out again, literally in a matter of seconds, as compared to the time it took to extract the star! After the star went in, it took me quite a while to get it back out again. The odd shape of the star obviously adds a lot to the difficulty. 

Hanayama rates the puzzle 3 out of 6 in terms of difficulty but I think it deserves a 3.5 maybe. It takes a while to get the hang of gripping one of the points of the star and slowly turning and easing it out of the cut-out. With practice, one can solve it repeatedly and I managed to do it several times quite quickly. There are two other write-ups on the Cage so you may also want to look at Brian's and Jeff's blogs.

12 Points To Insanity

I got this 6 piece interlocking wooden burr puzzle from Yallingup Maze, in Yallinggup, Western Australia while I was on vacation the last couple of weeks. Apart from the main attraction which is a large outdoor maze to amuse children and adults alike, it also has an indoor cafe cum puzzle shop selling a variety of wooden, metal and plastic puzzles (and games) including those from Hanayama, Philos, ThinkFun and of course from Mr Puzzle Australia.

What is really nice about the place is that you can sit and sip a cappuccino for a couple of hours and play with demo puzzles and games that are left around all over the cafe before deciding if you want to purchase any. Anyway, due to the limited time I had and in between watching over my 15 month old son, I played with around 5 or 6 puzzles before settling on buying this 12 Points To Insanity, as well as a Hanayama Cast Cage, an IPP27 exchange puzzle The Cube, a wood, string and ring puzzle called Tricky Dick and a 6 block burr called Just Six; all which I shall review hopefully at a later stage. Now back to the Insanity....

The Insanity measures about 3in x 3in x 3in and from what I think, is made of Australian cedar stained radiata wood which gives the puzzle a sort of orange brown look. Although the Insanity is made by Mr Puzzle Australia, the site doesn't appear to list this puzzle for sale. Construction and cut of the puzzle is very good and the pieces interlock nicely. This is a standard "diagonal burr" (thanks to George Bell for this info). I had a chance to "demo" this puzzle and actually managed to solve it in the cafe with the help of an enlarged photo of the puzzle in the solved state.

The version I went home with was a brand new one shrink wrapped! The puzzle description states the difficulty at level 3. I would agree. Although not difficult to solve, the Insanity does however require a fair bit of dexterity with both hands to get the 6 pieces in order to lock the puzzle together. I took a while to get to grips with the 6 pieces with two hands, three in each and kept dropping some of the pieces onto the table before finally assembling the entire thing back to its locked state. Pressing the pieces against my chest as a support helped a lot too!

While I am no expert or authority on interlocking burrs, overall, I would say the Insanity is a fun puzzle with sufficient challenge (at least for me). It can be solved pretty quickly and repeatedly once you have done it a couple of times and got the hang of it. Jeff has also commented on the Insanity on his blog.

Retro Plastic Twisty Puzzles Collection

Update 23 October 2017 - Dear Reader, please check out my new puzzle blog and e-store at http://mechanical-puzzles.com

For a change from the usual posts on wood and metal puzzles, I am featuring here a small collection of 7 different twist type puzzles all plastic and very retro!

Top Row L to R: Wisdom Ball, Gerdig UFO, Puck Puzzle,  Saturn Brain Killer
Bottom Row L to R: Brain Ball, Back Spin, Enigma

I acquired these puzzles after having seen them over the internet from time to time, my purchase criteria being based on their unusual design, uniqueness in their puzzling aspects and of course their vintage rarity. Added to this, their bright and attractive colours and round shapes were also key selling points.  Hence you will find there is no twisty cube-shaped puzzles here, which are not really my cup of tea anyway. There is also a fair amount of information that can be found on the internet about these plastic puzzles. For those interested in such plastic twist puzzles, there is an internet forum with a base of 2,000 members. I guess the likes of Rubik's Cube continue to live long and prosper!.

The Wisdom Ball, Gerdig UFO, Brain Ball and Back Spin came from a gentleman from the Czech Republic by the name of Milan Vodicka who has a site featuring an extensive number of plastic twist/non-twist puzzles for sale, some produced as far back as the 1980s. The Puck Puzzle came from the puzzle shop of Hendrik Haak, Saturn Brain Killer from Amazon and the Enigma from an Ebay seller who, at the time of this writing still has several of these puzzles left.


Wisdom Ball

This is the invention of Yang Iu-Hsin of Taiwan. It is a ball puzzle with 6 rotating circles, each comprising a different colour. In the solved state, each rotating circle has 8 number tabs in running order from Nos 1 to 8. The only exception is the red circle which has only tabs Nos1 to 7. In place of No.8, there is an empty slot to which a number tab from another circle can slide into. In the unsolved state, all the number tabs are of course jumbled up on each of the 6 circles.

The object of the puzzle is to take a jumbled up Wisdom Ball, rotate the coloured circles and slide the number tabs around and render the number tabs back in the correct order on each of the circles. This is but one of the 7 challenges available for this puzzle. Other challenges include arranging every tab to be the same number on each circle, and matching the same colour for both the number tabs and circles.

The puzzle is not unduly difficult and I had a lot of fun turning the circles and sliding the number tabs here and there. It came solved, so I was quite happy just to scramble it enough for me to have a decent feel for arranging it back to its solved state.

My copy of the Wisdom Ball  is well constructed and quality is very good. The surface is matted so that there is some texture and will not slip easily for those with sweaty palms. The ball is of a good size for the hands (diameter of about 3 1/4in) and all the coloured circles rotate smoothly.

The only grouse I have, and this is a minor one, is that to slide a tab, the two circles in question must be properly lined up so that the tab can slide across from one circle to the other smoothly, otherwise you will find that the tab gets stuck sometimes. However as I played more with the ball, I realised that after a while, one can easily get the hang of properly aligning the circles quite quickly and efficiently and solving becomes a much easier process. The Wisdom Ball is pretty rare so its worth getting if you come across one.

For more information on the Wisdom Ball, check out Jaap's Puzzle Page and Gabriel's blog. There is also a video review of the Ball on YouTube.

Enigma

A green stopper restrains the two
dials to prevent unintended movement

The Enigma is a one of those puzzles that is occasionally massed produced as corporate gifts or souvenirs, usually bearing the logo or name of an organisation or a company.

The puzzle is round with a diameter of 3 1/4in and 7/8in thick. Made of sturdy plastic, it consist of 3 parts; a top and a bottom circular dial with finger grooves along its edge, both which can rotate.  These two dials sandwich a centre disc with gear teeth. What the two top and bottom dials do is that when they are turned clockwise or anti-clockwise, they manipulate a series of internal gears within the puzzle which in turn will cause 8 small circles around the edge and a larger centre  ring, all on the top surface to turn in various directions. This has the effect of jumbling up the image printed on the surface of the puzzle. In the solved state, the image looks normal and nothing appears to be amiss. The 8 circles and ring have pretty tight tolerances and they are not obvious within the image unless you look closely at the puzzle. The image looks normal just as in the photo on the right above.

Once you start turning the top and/or the bottom dials, the image starts to get jumbled and becomes illegible (as in the left photo). The goal here is to rotate both the dials in order to get the image back to "normal". The puzzle is not as easy as it appears to be since both the top and bottom dials control the rotation of the 8 small circles (each dial 4 at a time) as well as the larger centre ring. So quite a fair bit of turning left and right is required, for both dials to finally line up the image again. If the image is a relatively complicated one (like the one here), this makes the puzzle even harder to solve.

Overall, the Enigma is a fun and unusual puzzle (I think great for kids too since it is plastic, safe with no sharp edges, loose parts or unduly heavy). I just wished I had been able to obtain one with a nicer image and colours and not bearing the name of some organisation, but alas, my Ebay seller had already run out of decent looking ones. See Jaap's Puzzle Page for more info.

Back Spin

Back Spin was manufactured by Binary Arts (now ThinkFun) in the l990s. It is a fairly large puzzle measuring about 6in in diameter and 1 1/2in thick. It is well constructed and the plastic quality of my copy is very good.

The puzzle consists of two flat rotating black discs joined together at the centre. Both the top disc and the bottom disc each have 6 coloured slots, each containing (in the solved state) 3 balls of the same colour. In total, there are 12 slots from both the top and bottom discs. However, at any one time, one of the slots (depending on whether you are looking at it from the top or bottom) will have only two balls.

At any one time, one of the 12 slots on the
Back Spin (for top and bottom) will only have 2 out of
3 balls such as the blue slot at 12 o'clock
containing  only a red and a blue ball

To play with the Back Spin, you are first required to scramble the puzzle to mix up the colour balls in their slots from both the top and bottom disc and you do this by rotating the 2 black discs, aligning the slot with 2 balls with a slot containing 3 balls and allowing a coloured ball from the 2nd slot to fill the slot which has only 2 balls. Now the 2nd slot that originally had 3 balls now is left with 2 and you find another ball from yet another slot (with 3 balls) to fill it.  And you continue doing this until all the balls in the slots are sufficiently mixed up in colours. To solve the puzzle, now your objective is to fill each slot with 3 balls not only all of the same colour but also that the slot colours on both sides of the discs match the colours of its  3 balls within.

The puzzle is not overly difficult but presents a fair challenge. However it can be a bit tedious since you are required not only to rearrange all 35 coloured balls back into 3 same coloured balls per slot but also into the slot of the correct colour.

After I had scrambled the Back Spin, I went about diligently trying to put everything back in order but at the time of this post, I still have not return it to the solved state....yet. Maybe I should have jumbled it less!! It's hard to describe the Back Spin in action so do watch videos of it; click here and here. Also check out Jaap's Puzzle Page; which gives the solution in very detailed steps. The Back Spin is no longer sold by ThinkFun. It also has a number of spin-offs (no pun intended) and imitations found for sale on the internet, so getting an original version may be quite difficult and would probably be via a private sale.

Puck Puzzle

For a puzzle with just one size, design and construction, I think the Puck Puzzle ranks up there with the Rubik's cube for having the most variants; perhaps even more than the basic Rubik's cube. The variants here I am talking about are the myriad of colours and graphics that adorn the Puck Puzzle in its many guises. If you did a Google search under Images for "Puck Puzzle", you will probably find no less than 15 different colours and designs of Puck Puzzles. My puck is the Blue IQ139. From what I can see from the Internet, there is also a Red, Yellow and Rainbow IQ139 puck.

The Puck measures about 3in in diameter and 1in thick and made of high quality plastic. Fit and finish is good and parts that are suppose to move all move smoothly. However, as you start twisting and turning, the puzzle becomes "seasoned" and the fit becomes less snug. Unlike a lot of plastic puzzles where parts are coloured using coloured stickers (eg; Rubik's Cube), the Puck's numbers are silk screen printed giving the puzzle a feeling of quality.

On all Pucks, the outer ring is made up of twelve separate sections (each shaped like a wedge) and together they can rotate around the centre circle.The centre circle is split into 2 halves and each half can also be turned 180 degrees forwards or backwards. In my case, rotating the outer ring in combination with turning either of the 2 centre halves has the effect of scrambling the twelve separate numbered sections.

The object is to rearrange the scrambled numbers back in running order from 1-12. To do this will again require rotating the outer ring and turning the centre halves. It takes a bit of figuring out to get the hang of rotating and turning the numbers to bring the numbers back in order again, since once you turn one half over, 6 of the top numbers disappear to the bottom leaving some to remain on top, so you may have a mix of numbered sections and blank sections. I scrambled the puzzle quite a bit but could not seem to get the numbers back in correct order again. I looked at Jaap's Puzzle Page and despite following his solution steps, can only manage Nos 4-12 in order. So now my Puck remains in a half scrambled state :-(. For a Puck in action, check out the videos on YouTube.

The Puck is not too bulky and quite pocketable. A portable puzzle to bring along to frustrate you on your travels!


Saturn Brain Killer

The coloured discs can slide along
inside the tracks around the ring

The Saturn puzzle consist of a ring with a recessed track on both sides. Within the track on either side are a number of movable discs. Each disc has a different colour on both sides. There are altogether 32 discs in the puzzle. In the centre of the ring is a bridge which can also rotate on its own axis.

The function of the bridge is to enable a disc to move from the top side to the bottom side of the ring and also allow a disc to change sides hence changing the colour from top to bottom or vice-versa. The object of the puzzle is to arrange the discs (with the help of the bridge) of 4 colours on 4 discs on each side of the rings. The Saturn measures 4 1/2in in diameter and is about 7/8in thick.

The bridge in the centre of the ring
transport the discs from top to
bottom and allows the disc to change
sides so the colour is correspondingly
changed

When I first unpacked the puzzle, I thought the puzzle was pretty simple, just rearrange the discs by pushing them around the rings and using the bridge to change the colours or flip it to the opposite side etc. Little did I realise that there are more than 8 colours (I had assume only 4 different colours for each side of the ring, hence a total of 8 colours for both sides).

As I continued playing with the puzzle, I found myself going around in circles (no pun intended) and it was then I discovered that there are more than 8 colours. There are actually 14 colours covering the 32 discs. This makes the puzzle very much harder to solve. Difficult because you can't remove the disc to see what colour is under a particular disc....the only way to know is for you to move a disc onto the bridge and then you can see the underside of it. Also difficult because you need to figure out which are the relevant 8 colours to solve the puzzle as intended.

After the usual scrambling of the colours, I tried to solve it but gave up after some time, not only because the puzzle is difficult, but also because the bridge keeps getting stuck and cannot rotate properly because one or more discs keeps getting jammed (half of the disc is in the ring and half onto the bridge). I wouldn't say the quality is bad, in fact the build of the puzzle is pretty solid and sturdy with the use of good plastic. The only complaint being that of the bridge and I guess its the way the puzzle has been designed.

I checked out Jaap's Puzzle Page for some explanation on how to figure out the colours in order to solve this puzzle, but unfortunately (through no fault of his) I can't quite follow his analysis and reasoning to determine which are the 8 colours needed to solve the puzzle. Jaap has listed the 8 colours on his site and once you know the 8, solving becomes relatively easy. Randomly trying to solve the puzzle by trial and error is not going to work as I also discovered. Now that I know what are the 8 colours to use, I am quite happy come back to the Saturn again another other day. While I thought this puzzle was a rare find, they are still available via Amazon.

For how the Saturn looks in action, check out this video on YouTube.

BrainBall

The BrainBall ("BB") looks like the planet Saturn; it consists of a ring of numbers from 1-13 (white on one side as in the photo and yellow on the reverse side). This ring encircles and can rotate in either direction around the ball. The ball itself consist of 3 parts, the blue portion which is flanked by two black circles (one larger than the other) on the sides and both these circles can rotate on its axis but not independently; ie both circles can only rotate together in the same direction at the same time.

In a way, the BB is similar to the Puck, the object of the puzzle is to unscramble and rearrange the numbers back in running order and in the same colour scheme. The BB looked to be promising at first but I had a hard time with it, not because the puzzle is difficult (yes this as well!) but I found the rotation of the number ring very stiff and arduous and I was practically using quite a bit of force to get it to turn around the ball. Flipping the black circles to turn the white numbers to yellow and vice-versa was only slightly easier. Having seen a video of the BB in action, I think its my own copy of the puzzle that is having this problem.  Notwithstanding,

I would say the quality of the puzzle, in terms of materials used and colours applied (no stickers here) is very good. Everything is strong and sturdy, perhaps too sturdy! It could certainly do with some hard twisting to "season" the puzzle. The BB measures about 3 1/2in across at the widest points and the ball itself is 2 1/4in in diameter. Size is about right in the palm of the hand.

I didn't spend a lot of time with the BB; I scrambled it just a wee bit to get a feel of how the puzzle works and given how difficult my copy was to manipulate the number ring around the ball, I didn't want to make things too difficult for myself and was content to get it back to its solved state quickly. According to Jaap, the BB is a "very difficult puzzle". Looking at his analysis of the BB, the various permutations that abound and the moves required to solve the puzzle,  I would not argue with his statement. There was even a website dedicated to the BB which now appears to be defunct, although Jaap on his site also mentions another link which has info about the BB. For its rarity, definitely worth getting one for keeps if you happen to come across a unit for sale.

Gerdig UFO
The Gerdig UFO ("GUFO") I think is probably the most mechanically complicated plastic twist puzzle I have ever come across. The design and number of moving parts integrated to form a workable puzzle is really quite amazing. The GUFO has its own website with a video, photos and a guide to how to play and solve the puzzle although you will probably require Google Translation unless you understand the Slovakian language.

The Gerdig UFO standing vertically
on its side to show the two halves
and the 8 coloured semi-spheres on
both the top and bottom halves

The GUFO consist of a white and thick flat "pancake" which is split horizontally in the middle into two halves with finger grooves for easy gripping. These two halves are connected via the centre and can rotate against each other. On the top rotating half, there are eight coloured semi-spheres protruding upwards. On the opposite, the bottom rotating half similarly also has 8 coloured semi-spheres protruding downwards. In the solved state, each semi-sphere is of the same colour, when viewed from either the top or bottom. When the top or bottom half is rotated, the 8 coloured semi-spheres move together along with whichever half that is being rotated. This has the effect of changing the colours of the top and bottom semi-spheres resulting in their colours being mixed.  In the centre is also a rotatable light blue dial with a red dot and within the dial is a white button. When the button is depressed, depending at which semi-sphere the red dot is pointing ti, that sphere will flip over to reveal its bottom colour; ie top colour goes to bottom and bottom colour comes to the top. The GUFO is about 4 1/4in in diameter and 2in tall. Quality and construction is very good and all the parts move smoothly and click into position without anything getting stuck so far....

The puzzle must first be ramdomly scrambled to mix the colours of the semi-spheres top and bottom.  This is done via rotation of the two halves, turning the blue dial's red dot to a semi-sphere and pressing the white button which will flip the spheres and mix the colours. Once its sufficiently scrambled, the fun of solving begins using the same type of actions that caused the puzzle to be scrambled in the first place.

The GUFO not only has an unusual design but it comes with 5 levels of difficulty built into the puzzle as well (ie something for the whole family as stated by the maker!). By increasing the level of difficulty beyond level 1, each time you depress the white button, more than 1 semi-sphere will flip simultaneously. At level 5, 4 semi-spheres (marked by 4 red dots) will flip at the same time. Each of the 5 levels can be adjusted by unscrewing the back plate of the white button to reveal a set of gear sticks which can be removed and placed at certain positions within the internal mechanism to set the puzzle to the desired level of difficulty.

The back plate removed to show the internal mechanism
and the black gear sticks which can be moved to different positions to adjust the level of difficulty

I scrambled the GUFO quite sufficiently at random and was able to solve it fairly quickly. But this was only at Level 1. I did not want to be too ambitious, so I didn't challenge myself to the other more difficult levels. Besides, I wasn't sure about messing around with the internal mechanism, just in case I jam something in the process. Overall I found the GUFO to be pretty fun and engaging (in my case at level 1) and watching the spheres flip and change colour when pressing the white button is pretty cool. I think I had a bit more fun with the GUFO than the rest of the twisties above (all which I enjoyed except maybe for the BrainBall), or maybe its just the fairly intricate mechanism that captivated me. If only someone would produce a metal version....now that would be really cool!

For another take on the GUFO, see Gabriel's blog. As usual Jaap has detailed information and analysis on solving the GUFO so be sure to check that out if you decide to acquire a GUFO. Its a pretty rare puzzle and you might still be able to get one from Milan Vodicka mentioned at the beginning of this post if he has any left or possibly from this site as well.