Sunday 4 March 2018

Not Getting Very Far - Some "Rest" Puzzles

Cross in cross
Over the last few weeks I have been struggling with the Popplock T11 - it is one huge heavy honking lump of brass and steel and looks wonderful but it's also one incredibly complex feat of engineering. I have been spending almost every evening playing with it and testing Einstein's Parable of Insanity (which incidentally, may not have come from the great man himself). There is an awful lot to the puzzle and after managing the first step in a very long sequence, I had gotten no further! In the end, I have had to resort to asking my own tamed (but still ferocious) lock expert, Shane Hales for little hints to help me on my way. Despite the depth of my own madness, even I cannot continue doing the same thing more than 2 or 3 hundred times and every now and then I have had to put the bloody thing down (gently because it could take out a floorboard) and play with something else.

Recently Brian Menold released a few new toys and I romped through his site and picked a few that really appealed to me. One of the first that jumped into my shopping cart of its own volition was the Cross in Cross burr designed by the amazing Yavuz Demirrhan (this does remind me that I still have a couple more that I bought from Yavuz to play with). I love Brian's board burrs as I mentioned in a recent post and the one by Yavuz looked fun - Brian said this about it.
"I always try to have a board burr in my updates. While this is not just a board burr, it is a three piece burr within a four piece board burr. I found the assembly of these to be way beyond my ability to memorize the steps."
With that endorsement, how could I resist? It also has the advantage of being simply stunning being made out of Box Elder (burr sticks) and Tigerwood (boards). So in the end, each time I have been forced to put down the Popplock to try and save the last vestiges of my sanity, I have picked up this. The solution is level so not trivial but I would hope that it would not prove too much of a challenge.

The biggest challenge with burrs is not so much finding the path, I find that I get lost in false pathways and it takes me a long time to figure out that I have taken a wrong direction. The Cross in cross starts with only a single move possible but after that, it is easy to head in the wrong direction - the incorrect route is also the easiest path to take and, to my shame, I got fixated on this pathway for 2 nights. The path is only 4 or 5 moves long but it just feels so right! Finally, after that, I gave up on it and found the correct direction and was rewarded with quite a few more steps. The whole thing expands quite a lot and thoughts of lifting the whole central 3 piece burr out appear in my fevered brain but despite looking possible it just never quite happens. Several moves are quite well hidden and need a little thought to find the pathway. Suddenly it clicks and the first 3 pieces come out.

The 3 burr sticks come out first (not as a whole burr)
The board burr remains in a near fully assembled state after the burr sticks are removed. It was a bit of a surprise to me that separating these pieces was another considerable challenge. The boards are a little unstable and can rotate but it is quite easy to hold them in place and investigate further. After another 15 minutes I was rather surprised to see that the boards were all identical - now that is a real touch of design genius!

3 sticks plus 4 identical boards
After separating them all, I expected that I would have to resort to Burrtools for the reassembly. Despite that, I always have a try at doing it by myself and I figured that at the very least I could reassemble the board burr hashtag shape. How hard can it be with 4 identical pieces? Erm!!! It proved quite tough for a poor dim doctor like me! It took me a whole evening in front of the TV with Mrs S and a pair of very sleepy cats before I realised that the beautiful regular pattern that I was trying to make was not possible - one of the identical pieces needed to be inverted and that was the only way they could all be intertwined. Phew! Maybe my dim(mer) switch had been turned up a notch? Having created the board shape, I then surprised myself by easily reassembling the 3 piece burr inside and collapsing it all back to the beginning. This is a TERRIFIC design and beautifully made by Brian. It is great to have in my collection and will look fabulous on display!

Another fabulous puzzle which diverted me from the Popplock was another of the Chinese 99-ring series by the incredible Aaron Wang:

Disordered Chinese Rings
Something looks "not quite right" here
In early February I showed off the fact that I had solved a couple of variants in this series. The Second-order and Third-order Chinese rings were a fun challenge which was related to the standard Chinese rings puzzle but made different and more challenging by the fact that each ring held captive not just the next along rod but the next two (or even three) rods. This meant that a whole lot of thought and planning was required to complete the sequence. The disordered Chinese rings mixed the whole thing up. Looking at the diagram (starting on the left) you can clearly see that the first ring covers one adjacent rod, the next ring covers 2 and the 3rd one covers 3. Seems like a pattern? It would seem so but that's as far as it goes. The fourth one reverts to 1 jump and this does not reach as far along the puzzle as the preceding ring. Let's just say this lack of a sequence, plus the fact that early rings travel further than later ones and also the fact that some rings end together makes this puzzle a huge challenge. It does require planning but there is a whole heap of understanding that goes with it too as it is easy to get to a position where a chunk of the puzzle is released from the shuttle and then no further moves are possible at all except to go back to the beginning.

I think it took me a week to solve this one - I kept channelling my inner Einstein and getting nowhere before the solution hit me like a lightning bolt whilst at work one day. After a night on call, whilst working on emails in my office (I was not fit to be let loose on patients!), I had a sudden epiphany and the whole solution came to me! Luckily I always carry puzzles to work for me and colleagues to play with during a few free moments. 15 minutes later I had this:

This one was great fun
The disorder is really obvious when you try to spread the completed puzzle out. The reassembly is just as much fun. I have done this a few times since to prove to myself that it is not a fluke and I love it. The 3 puzzles as a group are a brilliant set - Thank you very much, Aaron. I will have to get to work on a few more in the 99-ring series soon. These are horrifically complex and even my friend Goetz (who is one of the best at this sort of puzzle in the world) has struggled to do more than a few of them. Periodically, I search his amazing compendium of N-ary type puzzles to see whether he has solved any extra ones in the sequence and to gain some insight into the types of sequences involved (small hint - I never understand his descriptions!!!)

Right! Now I had better get back to the Popplock. I really don't want it unsolved after a year like my T10! Shane! Are you near your email???

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