Tuesday 13 May 2014

2 Burrs In A Corner

2 Burrs In A Corner

Logan Kleinwaks. For Logan's other designs, click here. You will notice he has some of the more unusual and interesting names for his puzzles such as "A Difficult Birth In Africa" and "No Electricity Means No Power". Now, how's that for uniqueness and originality?

Eric Fuller. Website www.cubicdissection.com. 41 copies were made, each priced at US$77, currently sold out.

Type & Classification
Interlocking; 3D Packing.

6.6cm cube. Hefty!

Materials & Construction
The box is made from Jatoba or Walnut while the pieces are made from 12 different hardwords, some really exotic unpronounceable ones ; Goncalo Alves, Bubinga, Cherry, Zebrawood, Mansonia, Mahogany, Granadillo, Leopardwood, Canarywood, Sucapira, Paduak and Purpleheart. Construction and finish is as per usual, excellent.


Very beautiful wood colours adorn this puzzle; that was my first impression when I opened the wrapping. A packing puzzle, already in the solved state...doesn't look that tough...no need for rotations, so Burr Tools can help should I stumble along the way. So far so good. I practice a bit here and there and manage not to lose my way disassembling and assembling. Photo documentation a must for added insurance. I break loose all the pieces..and all hell breaks loose!

Main Goal: Create 2 separate burrs out of the 12 pieces....Arghhh! . 

Eric Fuller states on his website that there are 28,540 ways to construct a single burr...I am not sure how he arrived at this number but its a LOT. However, only ONE way (single solution) to build the two burrs. In other words you need to find the correct combination of 6 pieces (2 sets) to make the two burrs! My senses kick in and I realise that...oops...Burr Tools can't help since I cannot determine which 6 pieces go for which burr. [Edit - Burr Tools in fact can do the job here to find the unique solution to both burrs....thanks to Goh Pit Khiam for this info]

This is one of those puzzles where trial and error ABSOLUTELY WILL NOT work!

The pieces don't look that intimidating actually...each one only 6 units long, with the usual cuts. Don't believe me? Check out www.puzzlewillbeplayed.com and you will find some puzzles with humongous burr pieces, with so many grooves and notches it giddies the mind. But here is where the genius of Logan Kleinwaks shows...simple looking pieces to create two normal looking burrs...but supremely difficult!

Needless to say, I needed the solution, which Eric promptly emailed me. That's how you are now able to see the photograph above with the two solved burrs!

Difficulty Level
Insanely improbable (Eric's words). Can I also add "Impossible"? ie without the solution or Burr Tools....

What else can I say? Difficulty level aside...well...for US$77, you get value-for-money 3-puzzles-in-1 made from colourful woods....that's if you can figure out the latter two.


  1. Actually, I think you can use BurrTools to solve these. You can tell BurrTools to include "0 to 1" of each piece, then it will pick the pieces which work. Hit the "Detail" button when you are setting up a puzzle. I suspect this is where the 28,540 comes from. You should also be able to set up both burrs in one BurrTools puzzle and solve the two burrs together problem.

  2. Hi George, yes, earlier in the day, Goh Pit Khiam emailed me to let me know Burr Tools can solve both burrs, similar to what you are suggesting, he said to define both burrs as the end result in BT. I think I will have to have two sets of identical pieces to give 2 burr results. I will give this a try at some point. George, do you have this puzzle?

    1. Nope, I don't have "2 Burrs In a Corner" ...

    2. George, Allard sent me the BT file with the solve for two burrs within single BT puzzle...works beautifully!

  3. Thank you for the write-up, Jerry! I really enjoyed designing this puzzle, and I am glad to hear from people who appreciate the beautiful craftsmanship of Eric Fuller. Regarding the unusual names of some of my puzzles, I hope they encourage great minds to think about the difficult puzzles of humanity and apply their problem-solving skills to those important challenges.

    For anyone trying to solve the simultaneous burr construction puzzle without BurrTools, a small hint follows. Do not read further if you do not want the hint. Hint: how many units can there be in a single burr? This hint will reduce the scope of a trial-and-error approach, but solving by trial-and-error alone would still be extremely difficult. I would be interested to hear of improved strategies. Additional hints could be provided in the form of pairs of pieces not in the same burr.

    To get even more value out of the puzzle, you can use it as a (single) burr construction set, guided by the analysis of Ishino Keiichiro at http://puzzlewillbeplayed.com/777/TwoBurrsInACorner/.

    1. Hi Logan, you're most welcome. Thanks for your comments and the helpful hints and Ishino's analysis. Strange, I did a search on Ishino's site but couldn't find your puzzle...now I think I know why

  4. Actually it is 28,451 including mirror solutions. I made a copy of this puzzle for myself. It is special!