This was both a fun and challenging puzzle that I have been playing with during the course of this week. Growing Triangle is the design of Andreas Rover, the man behind Burr Tools, a free software programme that has brought relief to thousands of frustrated puzzlers (myself included) and changed the course of history for designing and solving burr (and other) puzzle designs.
I obtained Growing Triangle from Andreas during the Puzzle Exchange at IPP35 in Canada two years ago. In Andrea's own words....
"This puzzle is inspired by "London Squares" which was designed by Li Zhunyou and exchanged by James Kerley at IPP34. Although I very much enjoyed the puzzle I spotted some "usability problems" and I want to fix with this design"
Growing Triangle is precision laser cut from 6mm clear acrylic< Made by Mr Puzzle, it consist of 12 irregular shaped pieces. Each of the pieces are also etched with markings to indicate the number of triangular units within. The finishing touches include a nice red drawstring pouch.
There are 11 challenges to the puzzle, simplest being to take 2 of the 12 pieces and form an isosceles triangle of 4 units length per side. Then take 3 pieces and form a triangle of 5 units per side, 4 pieces to form triangle of 6 units per side until all 12 pieces are used to form the largest triangle of 14 units length per side. Each challenge offers a unique solution and as you would imagine, moving from 2 to 12 pieces becomes progressively harder and painful. I have shown just the first two solutions here as an illustration of what this puzzle is about.
The first several challenges are not difficult and it is rather obvious which pieces are needed for the solve. From my personal standpoint it becomes "exponentially" difficult once you go past 5 pieces. The instructions do not tell you which of the 2, 3, 4, 5 and so on... pieces to use. You need to figure this out for yourself! But it does not require any form of random selection...rather if you study the puzzle sizes from the beginning, from 2 to 3 to 4 unit lengths and beyond, you will realise there is a trick to finding the area size of the next required piece as your triangle enlarges (grows).
So far I have grown my triangle to 11 units length per side using 9 of the 12 pieces. But I have since remained stuck at this level (but I am still trying).
Oh, and did I mention that you can use Burr Tools to solve all 11 challenges of the puzzle? :-)
Update 24 October 2017 - Dear Reader, please check out my new puzzle blog and e-store at http://mechanical-puzzles.com
Ray Stanton is well-known for his series of co-ordinate motion "pseudo-burr" puzzles, burrs that look as such but do not behave like a typical burr during the solve.
The Slideways Cube from Ray, which was also his IPP35 Exchange Puzzle is no exception. Physically it looks like an ordinary cube (interlocking) puzzle. It measures about 5.5cm on all sides and manufactured by Pelikan Puzzles out of Mahogany and Cherry. Consisting of just three pieces, each piece is a combination of straight and slanted cut smaller cubes/rectangles glued together. Quality, fit and finish is very good.
The object is to take apart the three pieces and re-assemble. Like Ray's previous puzzles of a similar nature such as the Quad Slideways Burr, Double Slideways Burr, one of the key challenges is to first discover how the puzzle would come apart. Then comes which part/area of the puzzle to press/pull in order to separate the pieces. Pelikan has done such a great job of construction that it took me quite a while to find the joint lines, which are so well hidden, where the three pieces meet; ie the starting point. The fit is snug (made more so by the high Singapore humidity) so it took some effort (and dehumidifying) to slowly ease the pieces outwards away from each other. It comes to a point where the pieces would release themselves and come apart.
Unlike the two other puzzles mentioned, the re-assembly for the Slideways Cube is not as difficult since the final shape to achieve is a cube and the cherry/mahogany combination has a surface pattern which also gives some indication how to pieces are to end up together. Moreover, with just three pieces, it is very manageable with just two hands. No clumsiness of handling here, unlike the Double Slideways Burr which had six pieces. (Hint: always good to photograph the puzzle before you start....and during solve...it will save you a lot of headache later). I have decided not to show the puzzle in mid-solve as this gives away too much. As of the date of this post, Pelikan does not list the Slideways Cube on their site, so I guess there is none available for sale. Not sure of Ray has any spare copies tho'
[Edit 26 March : John Devost has a copy available here]
Update 24 October 2017 - Dear Reader, please check out my new puzzle blog and e-store at http://mechanical-puzzles.com
Don't be mistaken. This is not about one of the most evil men in modern history, but rather the name of Rik van Grol's IPP35 Exchange Puzzle in Ottawa, Canada. Before anyone has anything to comment about the choice of name, here's Rik's explanation in his notes accompanying the puzzle:-
1. "Bin", which is short for "binary", refers to the solution method.
2. "Laden" is Dutch for drawer or tray
3. "Bin Laden" is the name of someone considered by many as the personification of the the devil. In a "devilish" streak, I took the liberty to ignore the "rules" of a true binary puzzle
4. "Too" sounds like "two" and means my second Bin Laden puzzle is equally "devilish"
(NB: Rik had designed the first Bin Laden puzzle for his exchange in Boston in 2006, reviewed by Oli Sovary-Soos here)
First off, the BLT is long and rectangular and entirely laser cut and glued together from layers of wood. It measures about 16.5cm x 5.5cm x 4.5cm. It's a secret opening box with 5 small drawers or trays. Standing vertically, it looks like a miniature cabinet with short legs to boot.
The object of the BLT is to "remove all five dice from their trays and close all the trays again". As Rik has mentioned in his notes, he has deviated away from a true binary puzzle design. For those in the dark about binary and such, check out Goetz Schwandtner's article on binary/n'ary puzzles.
I have played with a number of n'ary type puzzles before such as Cross & Crown 2013, Numlock and Schloss 250 so I kinda knew what to expect and how to go about solving. Simply put, there is a repeated sequence of moves that have to be made to arrive at the final solution. The challenge is to firstly discover that sequence AND then to remember it; one misstep and you are almost always guaranteed to go back to square one....in fact you might get stuck and not even able to start from beginning again.
Solving consist of pulling and pushing the individual drawers in and out of the box. The top and bottom panels are also able to move upwards and downwards (about 0.4cm) within certain limits and these affect the movements of the drawers. So in total you got 7 moving pieces (with mechanisms all hidden from view) to navigate inside the box.
I started off noting down on paper the early moves and at first there appeared to be some tangible sequence but after about nine moves, the sequence went out the window. What happened the next 45 mins or so was more trial and error trying to get the drawers opened. Each of the drawers do not either fully extend or retract but rather have various stop positions which adds to the difficulty. Proper alignment is also crucial, otherwise you might miss a move on one of the drawers. One by one I managed to get all the 5 dice out, but with a lot of effort. And thereafter in my attempt to repeat the moves, I got mixed up and it was another trial and error session before I managed to finally close all the drawers, and re-open them again. However, I just couldn't get the lowest drawer to open fully like I did the first time, so I was not able to return the 5th dice to it.
I will have to ask Rik for the solution or wait until the IPP35 Exchange Puzzle Booklet is out to find out how to solve the BLT in the fewest moves possible. Like Rik had pointed out, this isn't a true binary puzzle so as far as I could tell, there was no "repeated sequence" to be found and the puzzle behaved just like a burr, only thing is that the BLT's moves are hidden inside the box.
For a trick opening box, this is a great concept with the use of drawers and a "pseudo-binary" design to ensure a large number of moves to fully solve the puzzle. But the BLT is anything but short of very challenging and certainly something very different from the usual high level burrs.
The Karakuri Creation Group from Hakone, Japan is very well known for their fabulous and superb quality wooden puzzles and puzzle boxes. Equally well-known is that every year in the weeks leading up to Christmas, they will ship out their "Christmas Presents" to those who have joined the "Karakuri Club" and pre-ordered puzzles from a panel of designers, as early as the beginning of the year.
The puzzler selects the designer(s) of his choice, but would not know what sort of puzzle he/she will receive from their selected designer(s) until it arrives. It's a "surprise" to say the least! Not a cheap affair as well considering each puzzle is about US$100/- and there are usually an average of about 8 presents available per year. A full set will set you back about US$800/-.
For the rest of the year, the Karakuri Group designers release various designs and these puzzles can range anywhere from US$125/- to well over US$1,000/- a pop. Expensive would be somewhat of an understatement, but the design concept, theme, craftsmanship and attention to detail is simply incredible. Take a look around their site and you would know what I mean. From a puzzling perspective, some puzzles are pretty simple and provide little challenge for seasoned puzzlers but some designers like Hiroshi Iwahara create extremely challenging pieces.
Aside from exquisitely crafted puzzles, Karakuri also retails wooden puzzle kits. The one shown here is the Urashima's Box, which I purchased during IPP33 in Tokyo several years ago. I have had it for quite a while and totally forgotten about it until recently.
The kid is made of plywood and while there is nothing exotic about plywood, the pieces are very well cut and precise. It has even got a nice woody scent to it. It costs only about 2,000 Yen (US$17.50) but the quality is very good.
The kit comes un-assembled of course and this one has 16 pieces including the string. When fully assembled, it is a trick opening box. everything you need is in the kit except glue and here I used an inexpensive wood glue called Wessbond White Glue which dried quickly and gave good results. Smears and stains were easily cleaned off with a damp tissue. There is no need to go for epoxy and other fancy glues for this sort of work.
Although the instructions are all in Japanese, the diagrams are easy enough to understand for the assembly of the box and no translation needed. It took me no more than half an hour or so to glue all the parts together and another 6-7 hours or so for the glue to dry properly. The finished product was strong, sturdy and nice to look at, especially with the ribbon tied.
I don't think I need to explain the object of the box here and from photos i think you can quite guess how the mechanics of the puzzle works. So if you can't afford or don't want to shell out the dollars for the ala carte puzzles on their Michelin-starred menu, you can still own a Karakuri puzzle...get a kit! They are great fun and relatively easy to build and will astound your non-puzzling friends for sure!
Here's a nice sliding block puzzle that does not have a stratospheric number of moves. Its also a cute and colourful one and this was designed by Serhiy Grabarchuk, who is very well-known for his eye-catching and interesting looking sliding puzzle designs.
I have two of his other works which were reviewed earlier, his Sorter and One Fish Another Fish. I obtained the Sliding Arrow puzzle via a private exchange with fellow puzzler Dinair Namdarian, who also produced it. The puzzle is precision laser cut and well-made.
The Sliding Arrow measures about 14cm x 11cm and consists of a typical tray and 9 loose pieces. Unlike most sliding puzzles consisting of squares and rectangular shaped pieces, Serhiy had designed some of the pieces in the shape of a "bottle" and an "arrow". And this was fashioned into their shapes using translucent green acrylic for the bottle and yellow for the arrow. The "shaft" of the arrow is not another individual moving piece but cleverly recessed into the base of the tray.
The object is to get from the Start to the End positions as shown in the photos. Officially, the least number of moves to arrive at the final solution is 31. Not a lot compared to some other other sliding puzzles, for example, those from Minoru Abe. However, the moves are tricky and if you get the sequence wrong from the early stages, you will hit a dead end(s) and will have to re-arrange the pieces and begin all over again. This happened to me quite a number of times! Good thing most sliding puzzles have exposed pieces!
The Sliding Arrow is one of Serhiy Grabarchuk's more well-known designs and while the number of moves is not a lot, it is far more challenging than it appears.