Tuesday 24 January 2012

Kugellager 7

Kugellager 7 came quite highly recommended by my mate Louis whose wife had surprised him with one as a Christmas present. I already had a copy of its smaller brother, so when Wil offered them for sale soon afterwards, I knew I had to add one to the collection.
Although the family resemblance is impossible to miss, it is the implementation between the two that differs slightly. Whereas the first one is true to its name and uses actual ball bearings [Kugellager = ball bearing] to move between the levels, the bigger brother opts for short screw studs (they look a bit like large rivets that screw together) but retains the family name, modified with a clue to the higher order of this version – 7 as opposed to 5 levels.
 Somewhere in the middle
When mentioning the original Kugellager over here, I pointed to a paper by Goetz Schwandtner that covered the theoretical background to the puzzles by reference to things like Gray Codes and the like – and one of the really interesting things in the paper was a graph of the increasing complexity (read number of steps) against the level of the puzzle. Well that paper has already been updated to include a reference to the emergence of the bigger brother … for reference, the original was a level 5 puzzle and the newer, bigger badder brother is a level 7 puzzle – and the original had a pretty hefty 1250 moves from start position to end – whereas the level 7 version requires a slightly larger 4802.
Working your way through the solution is pretty straight-forward, if not a bit hypnotic and it definitely has an element of therapy in it. Moving the slider in and out while alternately tilting the puzzle forward and back to allow the pieces to move up and down between levels becomes almost second nature after a while. It probably says a lot about my OCD that I can’t leave it half-done, and actually found wandering through and then back again, quite amusing – what still intrigues me is my total inability to tell from looking at the current position how far away from either the start or the end position a particular point is – often when I think I’m getting somewhere, attention will fairly quickly switch to something I wasn’t expecting and end up making me feel like I’m going in reverse – and yes, I know that’s possible, but I think I’m still heading in the right overall direction. Promise.
The end
It’s a fun puzzle to play around with – but there’s one little piece of advice that might be useful – it’s worth spending a little time treating those screw studs with a bit of thread-lock or some plumbers’ tape to stop them working loose while you’re wandering backwards and forwards. I’ve found that a couple of mine tend to work themselves loose during the 4800-odd moves in each direction.

Addendum: Goetz has added a great page to his web-site that shows all of his n-ary puzzles over here.


  1. Nice article! I especially like the part where you mention the inability to tell where in the solution the current position might be. That's one effect I know only too well from the different Kugellagers!

    ... and thanks for the references to my Kugellager article. :)
    I have created a new page on my site, showing the n-ary puzzles I own in an overview by arity -- just click on my name.

  2. Thanks Goetz! I'll add a direct link to that page from the blog if that's OK... :-) allard

  3. Allard, thanks for the review. How long did it take you to complete the 4,802 moves?

  4. Hi Jerry - you're very welcome - it probably takes about half-an-hour to 45 minutes each way, but I haven't actually sat down with a watch on it... allard