Sunday 30 November 2014

The Kray Twins

The Kray Twins, designed by Steve Nicholls was also his Exchange Puzzle during IPP34 in London this past August. For those of you non-English folks who may not know who the Kray Twins were, they were notorious gangsters that were responsible for much of the organised crime in London during the 1950s and 1960s.

The puzzle is 3D printed in ABS resin and has six pieces comprising three congruent pairs in three colours. The puzzle holds itself together pretty well with tolerance between the pieces just right. This allows the pieces to slide pretty smoothly and no force whatsoever was needed for my copy. 

This one is a "diagonal" burr with sixty degree angles; thereby making it much more confusing and harder to solve than a traditional rectilinear burr, the latter, depending on the number of moves, is already by no means easy.

6 pieces all with diagonal cuts and 3D printed in red, white
and blue, representing the colours of the Union Jack :-)

This notoriously difficult puzzle has a level solution (total 40 moves), meaning it takes 6 moves to remove the first piece, followed by 10 for the second and so on. Once you get past the first six moves, you will understand why its called the Kray Twins. This one really stumped me for a long time. I just could not get past move six for some reason.

I contacted Steve for the solution and after studying the Burr Tools file; I realized where I had gone wrong. It was unlikely I could have solved this one on my own without help. Even with Burr Tools, focus and concentration was needed to get the moves right. I found the re-assembly even harder than the taking apart. The angles just seem to make it so much harder! 

Overall IMHO, a very difficult puzzle, but I am lousy at burrs anyhow. Experienced burrists may probably find it a less of a challenge perhaps.

Steve runs a 3D printing website ( so if you would like a copy of the Kray Twins, I am sure he would be most happy to make you a one...and possibly with the colours of your choice too! 

Tuesday 25 November 2014

Rightangular Jam & Japanese Puzzle Box

These two puzzles were gifts from a puzzling friend of mine who lives in Japan. A big thank to Frederic Boucher (hope you are reading this)

The first is Rightangular Jam, designed by Hirokazu Iwasawa who entered it for the IPP24 Puzzle Design Competition. Iwasawa, as you may already know, gave the puzzling community such award winning puzzles as the ODD Puzzle and Square In The Bag.

Start Position

Constructed from MDF for the tray and three of the triangles (the blue triangle is wood), this version is made for the broader market. The Rightangular Jam is part of a series of three puzzles of the same genre (albeit different solutions and varying levels of difficulty). The other two are Rectangular Jam and Triangular Jam

The object is to get the blue triangle out of the tray through a narrow slit on one of the sides from the starting position as shown above. Its like a sliding block puzzle except here you are allowed to slide the pieces in any manner, diagonal etc, not just rectilinear, so long as none of the pieces are lifted off the tray

I found this one pretty challenging and took a good hour or so to figure out the moves. Its certainly harder than the Rectangular Jam. But a really nice and "elegant" solution; no force required. 

The second puzzle is a Japanese puzzle box or "14 Step Mame Yosegi Traditional Japanese Puzzle Box". For the history and more information about Japanese puzzle boxes, click here.  My puzzle box is "mame" (ie miniature; it measures only 4.3cm x 3.2cm x 2.7cm) with a Yosegi design.

In terms of difficulty, not difficult even though it has 14 steps. Once you discover the pattern of moves of the box, you are well on your way. Mine even came with a little "reward" in the form of a cute wooden cube (love the tiny criss-cross design!)

Thursday 20 November 2014

Double Slideways Burr

It looks like any other ordinary burr. But don't let that fool you. The Double Slideways Burr (DSB) is one of the hardest co-ordinate motion puzzles around.

I got my copy of the DSB from Ray Stanton during the IPP34 Puzzle Exchange in London this year. Ray's exchange copies were made by Eric Fuller and the six pieces are cut from Walnut, Maple and Sapele. Very well constructed with fine edges and tight tolerances.

Why is it called the Double Slideways Burr? Well, because Ray had previously come up with the (Single) Slideways Burr, which consists of just three pieces. Although the DSB has double the number of pieces, the difficulty quotient is probably quadruple (or more) that of the SSB. I have never played with the SSB before, so I was thrown right into the deep with the DSB.

I spent the better part of two evenings figuring out the DSB, attempting different combination and orientation of pairs and pieces, looking for a way to "slide" the pieces together. After all, it must slide together somehow right?...given its called "Slideways". I even got my wife to help me hold some pieces while I grappled with the rest. But I got nowhere and eventually gave up. I emailed Ray asking for a hint. When Ray replied, I realized that I was way off tangent all the while. Even with his help, It took me another good hour or two before finally getting the six pieces to form the intended shape! 

This one is a real tough cookie. I happily emailed Ray a photo of my solved DSB and was quite pleased to hear from him that I am so far, only the fourth person he knows that has managed to put together the DSB. (Edit: as of 21 Nov 2014, there are 11 people who have solved the DSB)I don't intend to take it apart since I am not sure if I can re-assemble it again, and I don't wish to find it will sit nicely solved in my puzzle cabinet.

Let me put it this way...if you have never solved Ray's earlier puzzle, the SSB, well, the DSB will be very difficult indeed. But if you have solved the SSB before, then the DSB will still be very difficult indeed! And unfortunately, Burr Tools cannot help here. 

For those keen on acquiring an SSB or DSB, they are available from Eric Fuller's website for $15 and $39 respectively. For other co-ordinate motion puzzles reviewed previously, please click below:-

1. Choreographed Motion
2. Cross Box
3. 18 Dutch Mills
4. CM 13
5. Brass Ball
6. Cast Galaxy
7. Aroma

Tuesday 18 November 2014

Bob's 5x5 & Jerry's 4x4

When I first saw Bob's 5x5 during Nick Baxter's recent puzzle auction, I knew I had to get it. This was because I was a little surprise (and also a little disappointed) to find out that someone else had already earlier (in fact some 16 years earlier) come up with a design concept similar to my "Interlace 4x4" puzzle. More about the latter later.

The Bob's 5x5 I won at the auction is a reproduction of Robert Darling's IPP18 (1998) Exchange Puzzle. This is a huge puzzle, measuring a good 15.5cm (6.1in) square with a thickness of 3.5cm. Can you imagine the size of the box or crate needed to hold 99 exchange copies! 

It is very well made of wood (either teak or walnut I am not sure) and really solid and heavy. The bottom is even felt lined (so it won't scratch the surface it sits on). Displays nicely on the coffee table and one might even mistake it for a cigar box. Definitely well worth my $48 winning bid!.

Its a packing puzzle and the object is to pack 10 notched burr pieces (or sticks) flush into the box frame. 

Now to my Interlace. Its not a packing puzzle, although at one point in time I did consider making it so, but decided a free form interlocking solid with curved edges looked far more sexy. But as mentioned, the design concept is similar to Bob's 5x5. Until the Baxterweb auction in November, I had never even seen Bob's 5x5 or anything similar. The Interlace was something I came up with around September this year. 

My design consists of 8 board burr pieces that "interlock" to form the shape in the photo. I had it cut from 10mm thick plexiglass. While Bob's 5x5 pieces are two units thick, the Interlace is four. And both puzzles each have a unique solution.

The Interlace also became the starting point for my CrossRoads interlocking board burr with a level 12 solution. There are probably other puzzles out there with a similar design to Bob's 5x5 or my Interlace. If anyone knows, please drop me a note, thanks!

Thursday 13 November 2014

Borg Box (Stickman No.5 Puzzle Box)

This 3D printed version of Robert Yarger's extremely famous Stickman No.5 Puzzle Box (nicknamed the Borg Box) came to me courtesy of Brian Pletcher. For meaning of the Borg, click here. For a detailed description of the original wooden version of the box, click here.

Brian had modeled a copy of the original Borg Box for 3D printing by Shapeways. You can read his account of how he came about putting all this together (no pun intended). Thanks to Brian, I received my copy early this week. 

As it is made of 3D printed plastic, its a rather light puzzle but with a surprisingly solid feel, although there is that very slight bit of flex if you try to squeeze the puzzle hard (and during play), which can't be helped since it is made of plastic. Another reason for the slight bit of flex is that the entire Borg Box is made up of an astounding 78 interlocking pieces of various shapes and sizes. Notwithstanding, the pieces hold themselves together very well. Brian had done a good job of sanding and assembling the individual pieces to ensure a proper fit before shipping the puzzle to me. 

The Borg Box is an incredible puzzle to say the least. Even though I have never seen the original, just by looking and playing with the 3D printed version, I am absolutely astounded by the level of intricacy of the pieces and the way they were designed to interact with each other to form an interlocking 6-sided box. 

It takes 32 moves to open the top panel (as pictured) and a further 3 moves to be able to start removing each panel which can then be further dissected into 78 individual pieces. To open the top is not too difficult once you start to figure things out (like which panel is the top and which is the side) and where you need to slide what etc. But I still spent the good part of an evening just to reach this stage. I have decided I would leave it to another day for the total dis-assembly of the box, if ever that day comes.

By all accounts, the re-assembly of the 78 pieces is supremely difficult, so much so that when Eric Fuller made a limited number of copies for sale, he charged $50/- for any returned puzzle requiring reassembly. Thankfully Brian has generated a Burr Tools solution for the Box so there is help at hand, not if, but when its needed!

For another write-up on the Borg Box, you may wish to check out Allard's blog post. He is very lucky to be able to afford and own one of the real ones!

The Borg Box is available for sale through Brian. My copy costs $180, but it has since gone up in price due to the changes in pricing from Shapeways. 

Wednesday 5 November 2014


Update 23 October 2017 - Dear Reader, please check out my new puzzle blog and e-store at

I have had the Blockhead puzzle (designed by Bill Cutler) for over a year now. In fact I have three. One from Brian Menold, a plastic version from ThinkFun (marketed under the name "a-ha Square Fit") and the third I chanced upon at a local flea market; very cheap at $3/- but works.

Needless to say, the largest and best (and most expensive but value for money at only US$30/-) of the three in my collection is the version made by Brian. It's constructed from Yellowheart and Paduak. Very nice contrast of colourful woods here. Quality, fit and finish is very good and it even has fine Paduak detailing at the four corners of the frame. 

The Blockhead has been around since 1983 and is generally considered a must-have classic. Over the years, it has been mass produced and marketed under different names. Its one of the most manufactured puzzles around, made by different puzzle craftsmen at different times.

It's a packing puzzle and the object is to fit four square blocks inside the box frame. At first glance, it seems really easy....but don't be deceived. What looks simple never usually is. And in this case, the square blocks are not really all that square either. Each block has its sides cut at an angle, making them more like 3D parallelograms. Even the insides of the box frame seem to be lop-sided! And fitting them all flush into the frame is no longer simple after all.

For the Blockhead, I already had some clues on how to go about solving it even before I got my copy, having watched someone else playing with it, so I had a head-start. But notwithstanding, I still fumbled for a while after taking out the pieces and causally scrambling them before re-arranging them correctly for insertion back into the frame. One block will always refuse to go in. I would have definitely taken much longer if I did not have any prior hints because it is a very challenging puzzle no less. And certainly one that is quite different from other more traditional packing puzzles. And too bad, Burr Tools won't help here!

Saturday 1 November 2014

Alles Schiebung (All Shift)

This weekend, I played with another IPP34 Exchange Puzzle, the Alles Schiebung (or Google translated) "All Shift" from Hendrik Haak. Hendrik is an Ad man and runs his own advertising agency in Germany. On the side, he runs, his online puzzle store.

The puzzle consists of a five layer sandwich with six sliders and the goal is to navigate the sliders to their outer most positions. Cut into the sliders are maze paths with pegs within which restrict their movements. Somewhere residing in the middle is a small marble that will also hamper the movement of the sliders unless the puzzle is oriented correctly.

Designed and made by Jean Claude Constantin, All Shift comprises of laser cut wood, acrylic and plastic. Good overall construction and finish throughout. However, I did find moving the sliders a bit stiff at times, but I guess this can't be helped given the puzzle has multiple sliding and moving parts.

All Shift is a variation of the N-ary type puzzle; in simple terms, meaning there is a repeating pattern of moves in sequence to reach the solution. And you also need a decent memory to remember the pattern! I managed to solve the puzzle but I doubt if I had systematically applied an N-ary sequence. It was more random trial and error, with a bit of logic thrown in. The marble in my copy also popped out halfway (not sure how it happened, but its suppose to anyway) and went into the crevices of my sofa! In the same manner, I reset the puzzle to its original state, but left the marble out since I didn't know at which stage the marble was to be inserted.

Solved Position
The puzzle came with the solution on a business card and while it detailed the sequence of moves numerically (a total of 42), the accompanying photos on the card were just too small to make out the numbering of the individual sliders. Even with the aid of a magnifying glass, I could not make out the images. I have shot a note to Hendrik for help and awaiting a larger more legible copy of the solution..      

Overall a nice design concept with a different application of "N-ary". For those who are into this category of puzzles, the All Shift is worth considering. It is available on Hendrik's online store.