Saturday 8 June 2013

It's an 'L' of a Burr

The L Burr
A few weeks ago I posted that my Christmas wish had come true and a series of really beautiful burrs had arrived Chez Sadler. This blog post is going to describe my struggles with the gorgeous 'L Burr'. Why such a delay? Well, I have been busy at work and those of you who are friends with me on Facebook will have seen from my steady stream of photos posted that I have had quite a lot of new toys delivered recently! I have been going hell for leather with the N-ary puzzles and was pleased to read Allard's recent post about them and hopefully between the 2 of us we can get you hooked on them too. So it took me a little while to get around to writing about this one!

Recent deliveries have included:

Some N-ary and sequential movement puzzles
My puzzle pusher managed to get these for me. Here we have the amazing Kugellager 7 (a 7-ary version requiring 4082 moves to open and again to close - or even more after you get lost half-way through!) The 250 move N-ary lock by Jean-Claude Constantin and a small lock puzzle. The bottom puzzle is the IPP31 "Lager" but not as in beer! I haven't managed to come even close to solving that yet! All great fun!

Master Curvy Copter
This is a 4x4 version of the Curvy copter. The curvy copter was one of the first twisties I reviewed on this blog and it managed to get me completely hooked on twisty puzzles (in fact on my recommendation it has gotten quite a lot of people hooked on twisties). As I have gotten better at twisties, I have started to lust after the more complex challenges. This was designed by the amazing Eitan Cher and is available from his Shapeways shop. A discussion on the Twisty puzzle forum revealed that a friend, Burgo, who is a puzzle solving wizard considers it one of the hardest puzzles he has ever solved! This sort of tells me that I might have met my match!!! Gulp!

Oh Eric! What have you done to me!!!
After finally bribing HMRC to return these to me, I have taken delivery of a few more from Eric Fuller. Here we have 4 constrained burrs, a very nice copy of Kevin's burr - yes, named after me and designed by the amazing Jose W Diaz. Plus.... yes, more N-ary puzzles - by another fabulous designer, Goh Pit Khiam, we have the Tern key II and Binary key.

Houston, I think I have a problem!!!!!

So with the new deliveries and quite a lot going on at work recently, I have actually managed to control my urge to dive into doing Brian's masterpieces all at once! One of the puzzles I was really pleased to receive was the L Burr. It was originally designed by Junichi Yananose (one of the most prolific puzzle designers ever).
Brian said of this burr:
Junichi thinks the L Burr is one of his best designs ever; in his words “one of the most diabolical”.  Considering how many puzzles he’s designed over the years (and we’re sure a few of those remain unsolved around the world) this is a big statement!
It’s only 4 moves to remove the first piece, but that’s when the fun starts. This puzzle has more twists and turns than you can imagine. Back in 1990 he pioneered the first versions of his 6 piece board burr. In 1991 he then considered that he could divide the 2 x 4 rectangular shape on the end of each completed puzzle into two L shapes to create a very interesting puzzle. He remembers thinking this was so interesting that if he didn’t design something like this soon, someone else would.
Completely designed in his head it took about one full week to design this L burr.  He was concentrating so much on the puzzle in that week he says he even dreamed about it. Some people tried to make the puzzle and all reported back to Junichi that in theory the puzzle could not be assembled. This is incorrect, although the BurrTools software (a fantastic tool for analysing burrs created by Andreas Rover) still won’t be able to help you solve this one.
Mathematical theory suggests that the puzzle has a unique solution but in practice when made from wood we know there is a slightly sneaky second and unexpected one which Brian found during prototyping (much to Junichi’s displeasure!).  After that they worked together to change and improve the original design and it now has more twists and turns than ever before.
For both assembly and disassembly you will find that correct positioning is critical to be able to get the pieces in place without any force.
So as not to rely solely on glue Brian decided to add decorative splines to each glue joint (the blonde wood) for extra strength.  We think the benefits and the final look of the puzzle has been well worth the extra time and effort.
So how could I resist this puzzle?? Over the last year or so I have collected quite a lot of what is now known as "Turning Interlocking Cubes" thanks to Bernhard Schweitzer and another good friend of mine who wishes to remain anonymous! Having solved as many as 60 or 70 of this type of puzzle that cannot be solved using Burrtools, I thought I might be ready for Brian and Junichi's challenge.

First thing to say when you pick it up is "Wow! It is beautiful!" - it is made from Rose Alder with Queensland Silver Ash splines. Following this, you very quickly say "OMG! It's rather big and really quite heavy!!" It is not quite as big as the others that came out at the same time but at 13cm across it is a formidable thing. The fit of the pieces is amazing - the humidity in the UK varies a bit but is pretty steady most of the time and is almost perfect for wooden puzzles - no matter which way you hold this puzzle nothing slides freely. Pulling pieces in a certain direction starts them moving and they slide over each other and come to a stop with a very satisfying "Thwack" - Beautiful! After 4 moves a piece comes out and then you're in for a treat. This doesn't just require a few turns, there is a whole series of them and all the pieces have to be aligned exactly right to let it happen. If you are just a mm or 2 out then it will just not go. The sizing has been made so perfect that when you do get it right the turning is absolutely effortless after you discover the correct direction.

I think I have become quite good at these turning puzzles now and managed to take it apart in about 30 minutes.

Stunning workmanship!
Once in pieces, you can see that each piece is subtly different from the others and it will only go together in one way. I duly put it back! How pleased was I with myself??

"I'm a genius!" I thought.

I carefully arranged the pieces again having taken it apart for a second time and at that moment my 3 Burmese boy cats shot across the table as they chased each other whilst carrying a pair of my balled up socks!!! WTF!!

Once I got my heart rate back under control, I looked at the pieces to find that they were not in the carefully ordered positions - they were spread all over the table! I was going to have to work it out myself whilst having only the vaguest recollection of which pieces went where. This seems to be a recurring theme for me! I tried and tried for an hour with no success at all - In a panic I looked at the solution on Ishino's site, only to realise that the solution given was not correct for the new version that Brian and Junichi had devised! Aaargh, I was on my own. Back to work and once I'd calmed down and I had it!!! It only took me another hour!!!

Phew - that was quite a challenge - I really didn't want to ask the great Mr Puzzle for a solution!!! I'm afraid that being a limited edition these will not be available again, but if you meet anyone who owns this puzzle then ask them for a play with it. It is stunning to look at, beautifully made and cleverly designed to challenge but not be impossible for a normal human being to solve. (and YES! I am normal!)

Thanks Brian, I absolutely love it.


  1. Kevin, I had a similar experience with the puzzle, only that no cats were involved. :)
    The pieces of this version are a bit longer than the one on Ishino's site, so that solution will not work, as you already found out. However, it will give you some help with the target positions of the pieces.
    Back then when I tried to assemble the puzzle from the pieces lying around in a clutter, I managed to assemble it and it took me less than half an hour without any solution. So keep on going, you can do it! ;)

    Glad to see your package from Eric arrived already. Mine was probably one of the first order, but I guess I will have to wait for a few weeks until Customs is done with it. :(


    1. Yes Goetz, you are absolutely right. The pics on Ishino's site do show which pieces belong where. I did manage it in the end!

      I hope you get Eric's puzzles soon - you won't be disappointed!

  2. I don't often get enough time to really enjoy these puzzles but in this case I did because Junichi gave me his original prototype disassembled and asked me to put it together so I know the feeling of having all the pieces mixed up. But in fact that's how I found the alternative solution for the L Burr. I find burrs much more entertaining when given to you in pieces than taking them apart and trying to learn the solution from that.... that is of course if you manage to ever get them together :)
    Really glad you enjoyed the L Burr so much.

    1. You are a far far better puzzler than me Brian! I would seldom be able to solve a burr if given to me only as pieces.

      Luckily for me the making of a Burrtools file is just part of the fun!