Sunday, 12 March 2017

A Twisty Candidate for My Top Ten of the Year

Oskar's Crazy Comet
Last week I wrote at the end of my post that I was working on the Crazy Comet which had been mass produced by Lan Lan. My copy had been bought from my friend Marty but is also available from the various Chinese vendors if you live closer to them. I was originally attracted to it because it had quite a similarity to the Bermuda Megaminx puzzle series that I have begun to work through. However when I got my copy I realised straight away that whilst they are dodecahedra (like the Bermudaminxes) and also have some diamond centres that is where the similarities end. The Bermudaminxes ultimately require you to find a way to carry out at least a partial Megaminx solve where possible and this requires a few pentahedral centres. The Megaminx solve is actually pretty easy as it is effectively the same process as a standard 3x3 cube.

So having realised that the puzzle was neither Bermuda like or Megaminx like, I was a bit stumped. After that I was tempted to just scramble it and throw caution to the wind but after reading on Facebook that someone had tried a simple block building approach which was what I would have to do and had failed when they got to the top half. It was time to THINK© which was not something I am particularly good at. It took a while but I had an epiphany quite early on....the temptation with this puzzle is to orient it like the picture above BUT that's not the best way to look at it:

Curvy copter (an old pic)
A better way to look at the comet
Looking at the comet each face on the top is equivalent to an edge of the copter
The Crazy comet was effectively a shape modification of the Curvy Copter which is one of my all time favourite twisty puzzles. After realising that it was time to scramble the thing - I initially did what I had done with the Curvy Copter many years ago - I did only 180º turns and found the solve process relatively easy and quite pleasant - just like TomZ's original design the solve is mostly by intuition with a bit of corner work at the end - easy peasy! Flushed with my success I did a full scramble complete with double jumble moves as well as what I thought were simple single jumble turns. I had this fearsome object:

It's a curvy copter - how hard can it be?

A double jumble
Top right partial turn, front left partial turn then top front swaps pieces from each
OMG! I suddenly realised that I had missed something! I was able to do the bottom half of the puzzle by intuition as before but at that point I was scuppered - something was going wrong! What was going on? My friend Rline from the Twisty puzzle forum and with his own amazing YouTube channel pointed out in the comments last week that this was NOT a simple curvy copter mod. It was a Curvy Copter Plus mod - I had a think which hurt me quite a lot and I suddenly could see it. Unfortunately I had seriously struggled with the unbandaged part of that puzzle and this didn't bode well for my solving the comet. What do I mean by unbandaged? Look at these photos for an explanation:

On the right the CC has had the top right edge turned partially and then the top front too.
Note the right edge cannot turn back because the green petal is in the way
On the right is the CC Plus notice that the petal has a split in it? This is now unbandaged
The end result is that the corners and centre pieces can be swapped over (they also have orientation)
VERY confusing
The Crazy comet has a split edge piece and the ability to swap these edge pieces with the corners and also change their rotation. Aaaaargh! The only advantage of the Comet was that the swapped pieces didn't clash and prevent crucial moves or get one into impossible positions if one forced something beyond where it should easily go.

Now did this revelation help me? Not really! Being a "bear of very little brain", I continued with my original approach and worked on it by intuition. I had built blocks for the bottom ⅔ and positioned everything nicely. At least I now knew what my problem was and realised what I needed to do to progress. Derek and I had been chatting about his approach and he sort of confirmed what was required (he reduced the edges first). I started to reduce those edges and stored them in empty slots where I could but reached a point where I still had the corners in the edge positions and so every move would break the edges I had reduced apart. I needed a method. Think© damn you!

Thinking doesn't come naturally for me! I am a proper bloke and it hurts! But I was forced to work on it - I had a particularly bad night's sleep last week and in the morning I awoke with the knowledge.....I knew how to proceed. At the end of the fourth day of working on it I played and bingo! The reduction was done. It took a bit of doing and fiddling but still no special algorithms.

The final corners were still needing to be fixed and that should have been easy:

Cycling 3 corners is exactly the same in both puzzles!
Not a difficult algorithm at just a simple sequence that anyone could find
Once all the corners were placed it was just down to the final rotation of them:

A simple sequence fixes this
The same sequence is required
I was full of the joys of success and immediately scrambled it again to prove that I was a genius and it bit me....... there is a parity!

Aaaaargh! Just 2 corners to swap!
As you can see from the photo above there are only 2 pieces out of place - the corners opposite each other need to be swapped and this should be impossible! The "law of the cube" or maybe it should be "law of the twisty" states that it is impossible to move just 2 pieces. Therefore their must be a third piece to move but where?? After spending about an hour trying to convert this into a 3-cycle and of course failing I stopped and thunk. In the end I realised that this parity could only be produced if one of the diamond centres was the wrong way around - this is my third piece to be moved. How could I redo the puzzle whilst rotating the red (or any other) centre through 180º? This would be particularly tough as it is impossible to see the orientation. And then it hit me - there is a similar issue with the Curvy copter and all that is needed is a pair of double jumble moves using all the opposite faces - first double jumble the orange and green edges and then do it again with the blue and grey. AHA!!!!

That AHA! moment is what all us puzzlers are after and it is fabulous.

I can heartily recommend this puzzle for your collection - it is one that can be pretty much solved by intuition and thought and only the very simple sequences are needed to adjust the corners. It is just like the Curvy Copter Plus but much more fun and no blocking positions. I would even say that it might be a suitable puzzle for the non-twisty puzzle solver as there are no real algorithms required and only thought/planning!

Go buy it - you won't regret it!

Also you might want to have a look at my New Additions page to see why Mrs S is a little pissed off with me!

Are you interested in the cuboid twisty puzzles? I was asked for help by a correspondent of this site. He was struggling with the Witeden 3x3x9 cubic cuboid which is a really fun puzzle. In the end I had to create a pair of videos to help him on his way. If you are interested than have a look at these below. I am not very good at videos and have no idea how to edit them on my 10 year old iMac so these videos were each made as a single "take". I hope they are understandable.

First is the cubic reduction:

Then the top half of the cuboid solve (the bottom is very easy)

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