Friday 15 April 2016

Derek's Half Dozen

Derek's Half Dozen

Derek Bosch. Just did a review of his Pole Dancers in the previous post.

Manufacturer & Availability
Produced by Eric Fuller in 2013. A limited edition of 40 copies sold for US$69 each. Not available.

Type & Classification
Interlocking solid

6.5cm x 6.5cm x 6.5cm

Materials & Construction
Six pieces comprising three woods; ash, wenge and bubinga. Great looking! Excellent construction, fit and finish with tight tolerances. All the pieces slide and move very smoothly.

Externally it looks pretty just like an ordinary burr (save for the three pairs of different coloured sides) but the 6 pieces forming this puzzle are anything but ordinary. They are not your regular burr pieces with the typical notches and groves but rather odd shaped with loads of protrusions as you can see from the photo below.

This is an extremely difficult puzzle to take apart with a level solution, meaning it requires 26 moves to remove the first piece. I was stuck for quite a while during the opening moves trying to figure out things. However, something totally unexpected happened next. I am not sure if it is my copy that was a bit looser than intended (because my wooden puzzles are usually kept in a camera dry box for a few days prior to play). But midway through the solving, I was actually able (to my great and pleasant surprise) to rotate one of the pieces out without any force whatsoever. Having done that, the rest of the pieces came out quite easily thereafter. OK, so its not the way it should have been done and I am not sure how I did it...but too late...its over! Was it an accidental discovery of something in the puzzle that neither Derek nor Eric were aware off?

[Edit 16 April 2016: I am informed by Derek that apparently this rotation is well known and certainly not intended]

"Fiendishly difficult" is what Eric describes on his site. Fully agree. The movements of the pieces are absolutely dizzying! Without Burr Tools, my copy will have remained on the shelf in their separate pieces. If the rotation of that one piece had not been possible, I definitely would not have been able to take the Half Dozen apart. Even with the aid of Burr Tools, trying to reassemble the six pieces was still quite a handful (no pun intended). 


  1. If you rotated a piece out then you cheated I'm afraid! There is a well known rotation shortcut in that puzzle but if you ignore it and persevere with linear moves only then it is a wonderful design and very well made by Eric.

    Try again!!!


  2. While the rotation shortcut may help getting it apart, in my experience once the pieces are mixed up, you can't remember how to get it back together using the rotation. The burr "Extreme Torture" (ThinkFun Gordian Knot) is like this.