Sunday 11 December 2022

Several Twisty Challenges in One - The Dayan Gem X

It's Definitely a Little Gem!

Dayan Gem X
Yes, it's twisty time again! Don't run away - this one is really good and is actually solvable with a intuition alone and doesn't need any fancy algorithms or even making up any commutators. This Dayan Gem X is a fabulous little gem of a puzzle that can be scrambled and solved as a number of different challenges.

I would love to show you a photo of all of the Dayan gems but I have a bit of an organisation issue:

The gems are somewhere in there!
I can see a couple at the back but the thought of getting them out fills me with a sense of dread
Gem 1
The Dayan Gem series are a fabulous bunch of puzzles and this is the 9th to be produced - I have no idea what happened to the Gem 9 but I do hope that it will be coming. The Gem 1 (which I reviewed here way back in 2012) and Gem X look identical as truncated octahedra but they move differently. The whole point of all of this series is that they are interesting geometries and very interesting ways of moving. SuperAntonioVivaldi has made a fabulous summary video about the series). The original Gem 1 was a pure edge turner and had a similar solve process to a Curvy Copter. It was a fabulous challenge that mostly solved by intuition including the jumbling, double jumbling and shape shifting. I adored it...especially seeing as it didn't need a lot of fancy algorithms. Other Dayan Gems had similar truncated shapes and had face turning, deep and superficial cut face turning and even mixed edge and face turning. They were wonderful challenges that varied from easy intuition to mind-bogglingly difficult (especially for a bear of little brain like me). Every time one has come out I have been unable to resist adding it to my collection and frightened of them to varying degrees.

Of course, when I saw the Gem X come out I couldn't resist it and for once did not hold off scrambling and playing. As a general rule for you twisty novices or twisty-shy puzzlers, you should definitely embrace the edge turning puzzles. In my still extremely popular Twisty advice for beginners post and the follow up extension post I expounded on the delights of the edge turners. The addition of jumbling to a puzzle (with or without blocking) is so much fun and once you have got your head around the concept it really makes for extra interest. 

One edge and one face turn
So what does the Gem X add? First of all it turns on the same edges as the Gem 1 (see the purple and yellow edge is turned in the picture) and on top of that the square faces (of which there are six) also rotate (note the top left yellow face is turned. The end result of this is that we have 3 or even 4 puzzle challenges. Firstly I went for a face-turn only scramble and solve which, despite being extremely easy, was a lovely little challenge as a warm up for the more difficult puzzle scrambles.

After the face-turn only solve then, of course, there is a I went back to an edge only solve just like the Gem 1. It had been 10 years since I touched the original Gem and I had no recollection of the solve process at all. But keeping in mind what happens with the curvy copter, it is perfectly doable with just some intuition and thought.

After that then there is a mixed scramble of edges and faces but no jumbling and then attempting to solve that with only edge and face turns whilst avoiding jumbling in the solve (a jumble move has a very specific effect on the piece positions). Finally there is a full scramble with jumbling, double jumbling, and finished with shape shifting - GULP!

First of all, the face turning challenge:

Square faces only scrambled

The effect of face turning is to mix up the bicoloured edges and move them all over the puzzle whilst keeping the square faces intact. The solution to this challenge is pretty simple. It is effectively an octahedral version of the Dino cube and needs nothing more than my old favourite "up, up, down, down" sequence to move all those edges into place one at a time until the puzzle is left with a single 3 cycle which is also solved with that simple sequence. Stunningly easy and a perfect start to boost your confidence.

Next up the original edge (Dayan Gem 1) scramble. Like all edge turners the moving pieces remain in orbits and can be scrambled and solved logically just by moving the pieces within their orbits until you have 3 remaining to move into place and they solve with a simple intuitive 3-cycle. This, non-jumbling scramble was my second method of scrambling and solving. It is not difficult but it IS great fun. Then of course, once you have gained a little confidence then it's time for a jumble - this involves partial turns of adjacent edges and once lined up properly the edges can be rotated with shape shifting and pulling pieces out of their set orbits to add another facet to the challenge posed by this puzzle. The jumbling can be a double jumble which works like this and leaves the puzzle in the correct shape:
Two partial edge turns 
Then turn the central edge
End result 2 edges swapped
Performing an edges only scramble with double jumbling leads to a nice challenge - it looks much more scrambled than the face only scramble but it quickly becomes apparent that on the hexagonal faces 3 of the pieces are all in the correct place.
Edges only turned with double jumbles
Step one reveals it not to be too tough
The process of solving this puzzle is identical to the Gem 1 and if you have not bought that then there is no need to. It can be shapeshifted by single jumbling but I saved this for later.

One quirk of the double jumble solve is that occasionally it all solves leaving one or occasionally more edges flipped:
This is easy to fix if you remember the same thing on the Curvy copter
The reason for this is that the double jumbling can be done from 2 set up directions and therefore the solution is to redo the double jumbling twice. Extra fun for you.

Next up was a combined edge and face scramble that DID NOT utilise jumbling. Why bother with this? Because the next challenge is to solve the puzzle without using jumbling. It is not an easy challenge. The edge turned pieces are no longer within their orbits because the face turns disrupts the orbits. But, having scrambled it without jumbling I decided to attempt to solve it without jumbling:

It looks like any other non jumbled scramble
The difference here is that everything is scrambled and no simple turns will suddenly solve half the face pieces. I picked a hexagonal face and built it using a combination of face turns and edge turns. After that I basically worked my way up the puzzle in an almost layer by layer fashion adding pieces as I found them. I did not memories the colour scheme and had to work out which faces went where on the fly. Occasionally I would realise that I had placed pieces wrongly and did not realise it until I had 2 identical coloured faces adjacent to each other or reached a point where there was no bicoloured piece that would fit in the required space. This led to me rearranging hexagonal edges into different arrangements until I found a colour setup that was possible. I never got too far into it before realising my mistake (you could just memorise the colour scheme and avoid my pitfall). Once the colour scheme has been fathomed, then it, again, is mostly intuitively combining of pieces and working my way up layer by layer. Once I was above the equator line it began to get tougher. There was less room to move. Despite this there is a fabulous fun process that is STILL INTUITIVE! Or so I thought...

I solved the puzzle in this way a couple of times and was brimming with confidence until I hit an awkward moment:

Ooh! That shouldn't have happened.
I had to undo part of the top of the puzzle and reorganise it with one of the square faces turned through 90º. We had a parity caused by the fact that all the pieces on the square faces can be moved and if one of them is reassembled with the interior rotated then it is reflected in the exterior of the puzzle. I was scratching my head over that one for quite a few hours! All part of the fun.

Finally, we also have the ability to shapeshift by not pairing up the jumbles (i.e. single jumbles) which leads to a fearsome looking scramble:
Single unpaired jumble
Full face and edge scramble with ALL the jumbling
It looks horrific but having done the interim non-jumbling solves then it isn't too awkward to solve. The return to regular smooth shape just requires a bit of fiddling about until you learn how to line the gaps and the sticky-out bits properly and then twist them into each other. It is very satisfying to return it to proper truncated octahedral shape.

Having done that then the remaining solution proceeds just as I had with the combined scramble above. Mostly intuition is needed at the beginning and then towards the latter half it became obvious that I needed to use double jumbles to move pieces about as well as intuitive combinations of edge and face moves which rotate pieces into place. As long as you know what the double jumble does then it is fun
 to use it. The final process for this big scramble involves sometimes long complex setup moves which move the 2 pieces to be exchanged into the correct positions with respect to each other, performing the double jumble and then undoing those setup moves. Because I have the memory of a dementing goldfish, I had to write down a list of my setup moves so that I could undo them without mucking up all my hard work. 

The Dayan gem X is a fitting new member of the Gem family. If you are a collector then it is an essential purchase. If you are a twisty puzzler then it is an essential purchase. More importantly, for those of you who are just occasional twisty puzzlers and frightened of the more complex puzzles then this is definitely one to add to your collection and you can safely scramble and solve it in any of 5 different ways and have great fun playing and solving intuitively. Go for it - you won't be disappointed.

No comments:

Post a Comment