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 Post subject: Seemingly unpossible configurations
PostPosted: Sun Jun 09, 2013 12:26 pm 
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Came across two seemingly unpossible configurations today; one on a megaminx and the other on a QJ UFO. Neither puzzle was disassembled/reassembled to create the configuration. Thought it would be fun to throw them out there.

The megaminx has all other corner and edges solved. But I got this:

Image

What's the shortest algorithm to fix this? I can solve from this configuration but was wondering if there were a fancier solve like a simple edge swap.

The QJ UFO one is really fun too. All other corners, centers and edges solved except for one edge which is rotated 180deg:

Image

That image shows the edge pointed straight into the camera.

What's the shortest alg to fix this?
(hint for this one was a similar puzzle already discussed on this forum is visible in the background)

Anyone else come across similar weirdness on any other puzzles?


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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Sun Jun 09, 2013 7:24 pm 
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rplass wrote:
Anyone else come across similar weirdness on any other puzzles?
I'm interested to see the QJ UFO. it looks like a 4-sided version of the Pitcher Pentamid Shapeways puzzle. On the Pentamid it is common to get two corners flipped and the fix involves orbiting them around the five sides of the puzzle. For the QJ UFO, I'm baffled as I can't see how a single corner can be flipped on a dipyramidal puzzle, no matter if it has even or odd number of sides. I'm sure that having the puzzle in hand would help considerably. One guess is that this is the UFO equivalent of void parity. Another suspect would be solving it into the wrong colour scheme (i.e. mirrored), but I don't know if this is even possible.

I have seen my own share of puzzle weirdness. I will share this interesting case from my Void Tuttminx. There are two swapped edges in the last layer, as indicated. This can also happen on regular Tuttminx and I've wondered if it can happen on a Megaminx. Your case is a little different in that they are also flipped.
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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Sun Jun 09, 2013 7:40 pm 
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Pete the Geek wrote:
For the QJ UFO, I'm baffled as I can't see how a single corner can be flipped on a dipyramidal puzzle, no matter if it has even or odd number of sides.


Ah, the QJ UFO is a 3x3 shape mod. The "corner" you're looking at is the equivalent of an edge piece. There are four of those and eight other pieces which are also equivalents of edges which are simple rectangles. The corners are the small triangular pieces, and the centers are either the four-colored pieces with small triangles or the two-colored pieces that look like edges.

Bleh, after reading that I see how unhelpful it is. Just search for a good QJ UFO review/tutorial on youtube.

On your void tuttminx, is it possible to solve those 5 corners and retain the swapped edge pieces?


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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Sun Jun 09, 2013 7:53 pm 
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rplass wrote:
On your void tuttminx, is it possible to solve those 5 corners and retain the swapped edge pieces?
My educated guess is "yes", but I'm not certain. The corners can be solved at this point without changing the order or orientation of the edges, but I don't know if the funky state of the puzzle would cause a problem getting the corners cycled into their solved positions. I stopped and took photos here, because I recognized the case from my Tuttminx.

On the UFO/6-Axis Octahedron, your description gives me several more ideas. Mainly though, I was just looking at them in an online shop... :mrgreen:

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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Sun Jun 09, 2013 8:05 pm 
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Hold on, WHAT???

The megaminx case looks impossible. I can get that on the master kilominx, but that's classified as parity. Edges can only swap in 3s for a megaminx...

EDIT: Silly mistake. The edges were flipped not swapped. Oops.

EDIT2: For the UFO, are there any 3x3x3 edge pieces with no visible orientation?

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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Sun Jun 09, 2013 8:55 pm 
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rubikcollector123 wrote:
Hold on, WHAT???

The megaminx case looks impossible. I can get that on the master kilominx, but that's classified as parity. Edges can only swap in 3s for a megaminx...

EDIT: Silly mistake. The edges were flipped not swapped. Oops.

EDIT2: For the UFO, are there any 3x3x3 edge pieces with no visible orientation?


Yeah, it's not the corresponding configuration for the master kilominx, which would be:

Image

The megaminx has two edges flipped but in the correct location. The Master Kilominx shown above has two dedges swapped.

For the UFO, yes there are edge pieces with no visible orientation. They are the rectangular pieces on each face.


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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Sun Jun 09, 2013 9:04 pm 
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But wait, if you flipped the rectangular edges 180, then they would stick out right?

I don't have the puzzle but thats what i can guess.

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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Mon Jun 10, 2013 6:02 am 
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No, when the rectangular edges flip 180, one cannot perceive the flip. They do not stick out. I really do like the UFO and recommend it. It's things like this that make it more interesting than one would think from being just a 3x3 shape mod. Oh and the crazy shapes it makes!


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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Mon Jun 10, 2013 10:08 am 
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rplass wrote:
The megaminx has all other corner and edges solved. But I got this:

Image

What's the shortest algorithm to fix this? I can solve from this configuration but was wondering if there were a fancier solve like a simple edge swap.

There is probably something a bit shorter but here is the best I can do by hand:
[F, C', B2, I', H', B2, C, F', A, F, C', B'2, H, I, B'2, F', C, A']

The costly part is the [F, C] portion which is essentially "one move". Use of a slice move or a face anti-move might be able to avoid using the pair so much and cut this sequence down from 18 moves.

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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Mon Jun 10, 2013 1:40 pm 
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Megaminx notation is always a little iffy, but here's how I would flip two edges, it's a nice alg to know and works on cubes too:
R' U2' R2 U R' U' R' U2 L F R F' L'

If you do it on a 3x3 first it should be clear how to apply it to the megaminx.


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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Mon Jun 10, 2013 7:56 pm 
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bmenrigh wrote:
rplass wrote:
The megaminx has all other corner and edges solved. But I got this:

Image

What's the shortest algorithm to fix this? I can solve from this configuration but was wondering if there were a fancier solve like a simple edge swap.

There is probably something a bit shorter but here is the best I can do by hand:
[F, C', B2, I', H', B2, C, F', A, F, C', B'2, H, I, B'2, F', C, A']

The costly part is the [F, C] portion which is essentially "one move". Use of a slice move or a face anti-move might be able to avoid using the pair so much and cut this sequence down from 18 moves.


I think I translate that as:
L, R', U2, UL', UR', U2, R, L', F, L, R', U'2, UR, UL, U'2, L', R, F'

which inverts the UF and LF faces (not the orientation shown in my image)

Great! And thanks for the algorithm.


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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Tue Jun 11, 2013 1:43 am 
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bobthegiraffemonkey wrote:
Megaminx notation is always a little iffy, but here's how I would flip two edges, it's a nice alg to know and works on cubes too:
R' U2' R2 U R' U' R' U2 L F R F' L'

If you do it on a 3x3 first it should be clear how to apply it to the megaminx.

Thanks for that one, it flipped mine just like in the pic :)


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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Tue Jun 11, 2013 6:35 am 
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Nice! It works on the 3x3 and the megaminx, pretty nifty! Will now try it out on many other puzzles.

Thanks for the algorithm!


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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Tue Jun 11, 2013 3:06 pm 
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Quote:
Megaminx notation is always a little iffy, but here's how I would flip two edges, it's a nice alg to know and works on cubes too:
R' U2' R2 U R' U' R' U2 L F R F' L'



It looks pretty good on a 7x7x7.
Image

edit: I also used it to Superflip a Gigaminx

Image


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 Post subject: Re: Seemingly unpossible configurations
PostPosted: Wed Jun 12, 2013 1:19 am 
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That looks so pretty! :D


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