Sunday 11 September 2022

The Limcube Fission Skewb

A Skewb Which Doesn't Solve as a Skewb

The Limcube Fission Skewb
Stuck after 3 steps!
I bought the Fission Skewb way way back in May this year along with a few others and have not touched it apart from to explore what it does when it moves. Why buy it you might ask? I adore these fancy new twisty puzzles! The technology in their design and manufacture is incredible and there is so much more to them than the old style Rubik cube. BUT I am a simple puzzler who is not terribly good at most puzzling and the problem with the new twisties is the very thing that attracts me to them...they are just so so complicated. So many things move in so many different ways and I am terrified of scrambling a mess and getting totally stuck. I know that the internet is full of solution videos but I really don't want to cheat like that. So I waited until I had some courage - plus I recalled that someone had said on FB that this particular puzzle really isn't that hard. I had been playing with Angry Walter and after the first 2 or three steps had gotten completely stuck needing some more of that darned Thinking© so I decided I had better try another puzzle or else not have a blog post for today.

I picked up the Fission Skewb and reminded myself of what it does. It is of course a deep cut corner turner (hence the skewb moniker) but also is an edge turner. I would like to say that it is similar to the Curvy copter but it is not because the edge turns to not overlap with each other...interesting!

One edge turn followed by a skewb turn
A partial skewb turn with an edge turn
You can see why this frightened me!

As usual, I started out with a gentle exploration trying to ensure that I was able to undo any moves I had done to get back to the beginning and as usual I got lost within about 2 minutes and ended up with a mess that I couldn't back out of! Aaaargh! Well in for a penny...

That was a really silly thing to do!
After my initial panic I figured that I had better get rid of all the spiky bits and make it cube shaped again. At this point I realised that some of the V shaped edges are now obstructing some of the Skewb moves and a bit of planning is required to allow the wanted moves to occur. It's not hard but needs to be watched for. Some of the straight edges can be formed by just lining up to wonky ones and Skewb twisting to make them straight. After the easy ones were done then the remaining ones were a little awkward because straightening them broke others but in the end a little thought© and intuition got this sorted out and I now had a scrambled cubic puzzle.

What approach was needed now? Do I reduce it to a Skewb by solving centres and then making the edges up and finally solving as a Skewb? I thought that this seemed like a good approach because creating the Skewb centres is pretty easy:

Skewb centres created and placed
Wrong approach
It only took me about 5 minutes get all the centres in place - I was on a roll! Maybe I am not a dunce after all? Hahaha! What a ridiculous thought! Having done that it was time to work to put the edges in place and... Bloody impossible! I could put them in no problem but each time I did so it removed the centre edge pieces that I had already placed and after placing a few of these outer edges I couldn't place more without destroying what I had done. Yes, I know, this is the perennial problem with twisty puzzles but I had no fancy algorithm and could not work one out on my scrambled puzzle. Oh no! Was I going to have no blog post? I had to keep trying.

I scratched my empty noggin and then removed the splinters from my fingers before having another Think© and decided to try the outer edges first. Initially I was not sure about this approach because it seemed such a difficult thing to do but in the end it was a nice intuitive thing to do requiring no algorithm and just an easy three cycle of the pieces. It got a little more awkward as the final ones needed placement but really not tough and just a little figuring out.

Outer edges all placed - quite easy really
So how could I move the inner edges around? I searched for some kind of 3-cycle that would work as it had on my abortive attempt but I could not find one easily that would not destroy what I had. At this point I had a brainwave which is very unusual for me - the word "commutator" floated into my head and I realised that there was one very easily available because of the simple Skewb centre swap. Performing a simple Down, Down, Up, Up using the top front corners as axes moves the centre squares about.

That bottom front edge only has a single white edge in it
Rotating that edge and undoing the center swab does this
A simple 4 move set up followed by an edge flip and undoing that 4 move set up produced exactly what I needed. Time to work through it. Mrs S was much annoyed by me reciting Right Left Left Right Flip Left Right Left Right over and over again. Sometimes she was so fed up with it that she would randomly call out Left or Right to confuse me which, of course, worked very well and I descrambled the bloody puzzle! After amusing herself a few times doing this I growled at her and she let me continue in peace. Phew!

Nearly done - about 8 to go
As I worked my way through it I had to do set up moves to get the triangles in the right place for the commutator to work but surprisingly complex setup moves were never required. At the end I was left with just 3 triangle edge centres to place and needing a single setup to make it work.

R->B->O required.
The edges are not placed correctly but a single Skewb turn fixed that
After another 10 moves and it was done! Flushed with success, I immediately did it again and again. This is quite a fun puzzle and is really not that difficult once you have that realisation that a simple commutator is required. It would have been better to have realised it early on before I scrambled the puzzle but the actual sequence is so simple that I was able to find it even on a scrambled puzzle.

In the end, this is a Skewb variant that doesn't rely on any Skewb methods to solve it. This hit me by surprise and actually added to the enjoyment because Skewbs are very confusing to me. It is definitely worth any puzzler buying - if you are a true twisty puzzler then it is essential (if not terribly tough) but if you only dabble in twisty puzzles then this is a nice one to try before you get into the really tough ones.

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