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New megaminx scramble notation

Stefan

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I invented and described a new megaminx scramble notation and suggested to use it in competitions:
http://www.worldcubeassociation.org/forum/viewtopic.php?t=368

Feedback both from megaminx experts and novices is welcome, the latter are important because judges are often not the experts and they're the ones who'd have to use the notation. Especially a comparison with the current notation would be useful.
 
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DanHarris

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Hey Stefan, not much to add, its a great idea!

The only tricky part I found were the z2 turns on the megaminx, on my first try of scrambling I messed this part up I think, and because I was concentrating on the rotation, I think I also forgot which line of the scramble I got to.

So I have a couple of suggestions. If you were to present the scramble like this, number the lines so it is easy.

Lars V also came up with a very nice suggestion, why not do y instead of z2? We trialled it and it seems to scramble the megaminx just as well, and it was much easier to follow the scramble this way since we could feel our way around the puzzle, and keep our eyes on the scramble 100% of the time.

So I guess I had a bit to add, but what do you think? I think the y is much easier than the z2, so if it "scientifically" scrambles the megaminx just as well, I think it is a better option.

DanH

P.S. I had trouble registering on the WCA forum, so maybe you could pass my comments on to that forum?
 

Stefan

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I do the z rotation like this: Left thumb and index finger hold that top left CEC triple. Right thumb and index finger grab the opposite CEC triple. Then I rotate the puzzle while holding these two triples, then the left hand takes over the CEC triple from the right hand. I don't look at the puzzle for this.

I also had a bit of trouble going to the correct next line but I solved that by adding an empty line in the middle, i.e., after five lines. I've read that humans can identify the number of objects immediately and without really counting for up to five objects only, I think this might play a role. I kinda dislike the idea to number the lines because that'd be another thing to occopy your mind. Try adding the empty line in the middle and doing the z180 like I described above.

Don't know how y compares to z180, but it's an option that could be analyzed as well.

With the newest tiled Meffert megaminx, if U/L = white/brown, then after the z rotation U/L = yellow/red.
 

masterofthebass

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I still cant' get this notation down. I don't have a Meffert's Minx, so I tried using Erik's site. I assumed that white was opposite yellow and red was opposite brown. I don't think that's right, because I end up only scrambling the one half.
 

DanHarris

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Lars and I tried the scramble, and we both came out with the same configuration :)
Great! And how long did it take you?
Not much longer than a minute I think. With practise it can be much faster, but I think the idea is that a complete novice could do it in a fast time, because not many people will want to "practise megaminx scrambles"

Dan
 

Jack

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Oh, didn't understand that R and D were the whole puzzle except for the one face. Now that I read the description again it makes sense, I don't know why I couldn't figure it out before. It seems like a great scrambling system, it is much faster than the other notation!
 

Erik

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That's a good idea Stefan! Still I have 3(4)comments:
1. personally I do it completely mirrored from what you do and hold with my right hand mostly (personal thing)
2. the scrambles seem a bit long..
3. why are the y turns actually anti-clockwise? On a 3x3 a y turn is like U not like U', would make a bit more sense to me if a y was actually like a U on minx too.
(4) this is much faster than that old a C d2 G3 thing :)
 

Stefan

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I made Y the direction this way, because ... um, by mistake. Well, at least I didn't realize it until you said it. I think I accidentally did it this way because then ++ is always the same movement for the turning hand (otherwise D++ and Y++ would feel like opposites). What do you think? I might change it. Or Ron might. For the scramble quality it actually doesn't matter which direction you consider Y, as long as you're consistent.

Yes, the scrambles are long. Not 180 moves, though, but 105 (including the Y rotations). Indeed this is because we don't know yet what length is sufficient for high quality scrambles. But we don't really know for the current official scrambler/notation, either. When I first published mine, I chose 100 moves because that's what I've been using in practice for years (with my humanrandom scrambling, not computer generated). I'll do a quality analysis next, as I realized this fits neatly into my diploma thesis. Then we can hopefully reduce the length with confidence.

And yeah, it's much faster. I especially love parts like R++ D-- R++ D-- R++ D-- (i.e., alternating directions), that feels so neat.
 

Kenneth

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Someone of us Sweds needs to learn to scramble the mega before the Cube Day. The only ones of us who scramles the puzzle are Kåre and Gunnar and I'm sure they like to compeate so they won't do...

If one of us have to learn to scramble the mega, why don't use this new method, why not let it come to it's first test at the Cube Day?

Is that Ok by the WCA rules or does it needs an formal decision first?
 

AvGalen

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Article 4: Scrambling

4a)A scrambler must apply the scrambles.4b)Puzzles must be scrambled using a computer-generated random scrambling algorithm, that must be kept secret for all but the scramblers.4c)Standard metric for scrambling and solving is Half Turn Metric, where each move of 1 side counts as 1 move, and inner slice moves as 2 moves.4d)Cube puzzles must be scrambled with the white (or the lightest colour) face on top and green (or the darkest connecting face) on the front.4e)Competitors must solve the same scrambles per round. At the main judge's discretion, scrambling algorithms in preliminary rounds may be randomly chosen from a pool of scrambles, for example to prevent cheating in large competitions.4f)The number of moves to scramble a puzzle must be:
PuzzleScramble length (Half Turn Metric)Program2x2x2 Cube25 movesScramble program3x3x3 Cube25 movesScramble program4x4x4 Cube40 movesScramble program5x5x5 Cube60 movesScramble programClock14 moves
with random changes of upper and lower wheels,
and with random pin positions at the endScramble programMegaMinx60 movesScramble programSquare-140 movesScramble programPyraminx25 movesScramble programOther puzzlesAvailable on request. All scramble programs kindly provided by Jaap Scherphuis and Syoji Takamatsu (Pyraminx).
All scramble programs in a zipped file.
4b) says scrambles need to be generated by a computer program (and be random).
4f) says megaminx needs 60 moves (and provides a computer-scrambler)

Technically you could use Stefans scrambler with 60 moves. 100 moves would not be allowed.
Practically I think a discussion with your WCA delegate should clarify this.
 

masterofthebass

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Using Johannes's scrambler on the 15x4 setting, which is 60 moves, the 5 scrambles I tried seemed to be sufficiently scrambled. I visually can't tell any difference between the official notation and the new. On the first scramble, there are only 2 CE pairs matched up but of 2 completely different colors. I'm not sure how to go about the math of scrambling, but I'm pretty sure that 60 moves can be considered sufficient.
 
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