Sunday, 25 February 2024

An Icosahedral Puzzle for You Because I’m an Eejit!

Icosaminx with my own colour scheme
Don't they look great?
This is a fabulous puzzle - both in looks and in solving but I am writing about it with a heavy heart...I had not actually intended to write about it this weekend. I have to admit (yet again) that I'm not terribly bright! I have spent weeks on my solving odyssey of the Brass Monkey Sixential Discovery puzzle and really thought that I had it beaten (it took me 3 weeks to find the first step!) and whilst uploading my photos and looking at what I had done and the pieces I had found (OMG there are so many pieces!), I had this sneaky suspicion that I was missing something. I checked Allard's review and realised that I am truly a rubbish puzzler - not only had I taken an obscenely long time to get to where I was but I also had convinced myself that I had reached the end when I really had not and in retrospect it was obvious! Aargh!

As a result of this, I am having to discuss the Icosaminx which looks fearsome but is a minor challenge compared with the recently purchased sequential discovery puzzles that I am failing at. 

Most puzzlers seem to be geometry freaks (another reason that we are "not normal") and with a large number of tetrahedral, triangular prism, cubic, cuboidal, pentagonal prism, hexagonal and dodecahedral puzzles there is always room for something with another wonderful shape and yet more sides/vertices. Enter the Icosaminx...who can resist a 20-sided puzzle? Not me! I had to buy it as soon as I saw it on sale. 

As you can see, it's a corner turning puzzle which means that it is EASY to solve despite it's looks:

Corner turning makes for an easy puzzle
The effect of being corner turning means that the only parts that scramble are the face centers and the edges in triads. My usual approach to any twisty puzzle is to explore simple move sequences first and undo them and look at the effects to see how they can be used. Often I scramble by accident but within 5 minutes of performing an up, up, down, down I could see that those triads were being moved around like any edge piece series would. This is useful as the edges would be easy to place but what about the centres? Remembering the easy approach to commutators that I have learned many times I could see that with so many vertices, it would be easy to turn one and move a single center out of the triad and undo the up, up, down down which would make for a nice easy 3-cycle of the centres. 

Even this can be built partially by intuition

Hooray! within just 5 minutes of playing with the puzzle I had a beautiful solution approach. I would orient the corners, build up most of the bottom half of the puzzle by intuition and block building (this is easy because there is so much space on a 20 faced puzzle - I even was able to do this on the incredible Eitan's Star from many years ago.

Once half of it is built by intuition, I can then 3 cycle to place the edges and finally use my 10 move commutator with a few easy setup moves to rotate all the centres into place. I figured that taking 5 minutes to work out how to solve a twisty puzzle was pretty brilliant of me and then I failed the Brass monkey 6! Sob!

Time for a scramble:

It looks great scrambled and much harder than it actually is
Having admired the apparent chaos of so many pieces, I set to and am gratified to tell you that it really was as easy as I have told you. It's a bit laborious with so many pieces to place but a remarkably satisfying puzzle to solve. It took about 15 minutes to complete and left me with a big grin. I have taken it to work to show off and yet further convince my colleagues that I am a genius. They look at the puzzle with horror and then amazement when it is solved so quickly. At least some people think I am a genius whereas the puzzling world, my poor readers, well know the truth of my meagre skills.



As a follow up to last week's blog post, I can tell you that the puzzles I reviewed from Pelikan went on sale and as expected the really fancy ones sold out very quickly. I have been told that Jakub and Jaroslav intend to make more copies of the MRI and Matchbox Playground (and maybe the Filling V) in the future. Keep an eye out for them.

I did manage to finally solve the MRI with a very big smile on my face. I had completely missed something in the week that I had it and when I found it laughed at the simplicity and beautiful implementation of the mechanism:

It took me over a week!


6 comments:

  1. Maybe I am missing something, but isn't this just a megaminx with oriented centers a.k.a super megaminx?

    By the way, I am just wrestling with the mf8 "deceth" cube, an interesting beast indeed.

    Cheers Rupert

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    Replies
    1. You might well be right about the equivalence. I am terrible at being able to see such things and always have to work from scratch unless someone tells me in advance.
      I’ve been told about the DeCeth cube and it looks fun but probably completely impossible for me even without jumbling.

      Delete
  2. It helps to know the concept of dual polyhedrons: the Centers of one firm the corners of the other. The octahedron ist the dual of the Cube, and vice versa. The icodahron ist the dual of the dodecahedron.

    So the face turning octahedron ist equivalent to the corner-turning cube (rex-cube). Note that there may bei differencess in which pieces require orientation, and some pieces may be equivalent in one version, but distinct in the other.

    Rupert

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    Replies
    1. I have studied enough maths to understand the concept of duals but knowing such a thing does not actually help me solve as the transformation is too difficult to keep in my head.

      Delete
  3. About the deceth cube: yes you can!

    Or, as written in the tombstone of a famous mathematician "We must know. We shall know" (Original is in german, "Wir müssen wissen. Wir werden wissen.")

    ReplyDelete