Message #1195

From: Andrew James Gould <>
Subject: Re: [MC4D] Re: Tetrahedral prism {3,3}x{}, 3 layers solved
Date: Sun, 03 Oct 2010 12:29:50 -0500

3) This 180-degree rotation is possible as well. It’s the intersection of two triangular prism faces. In the {3,3}x{} 3, 5 lines of triangular prism stickers in each of those two faces (3 lines right side up, 2 upside down–15 total stickers from each face) will stay in that face, but rotate 180 degrees; 6 stickers in each of the tetrahedral faces get rotated to the other tetrahedral face (that’s 3 edge tetrahedral stickers, 2 octahedral stickers, and the central tetrahedral sticker from each face); and in the remaining two triangular prism faces, 2 lines of stickers from each face (one line right side up, one line upside down–6 total stickers from each face) get rotated to the other triangular prism face.

5) Just for kicks, I verified that yes, the currently allowed face rotations as well as the mask layers are possible in the {3,3}x{}.


—– Original Message —–
From: "Andrew Gould" <>
To: "4D Cubing" <>
Sent: Thursday, September 30, 2010 1:21:39 AM
Subject: RE: [MC4D] Re: Tetrahedral prism {3,3}x{}, 3 layers solved

Re: 2) Actually, I just realized you can currently do this twist type in the {3,3}x{} as long as the length is 3 (or greater). You can do it by holding down ‘1’ & ‘2’ (or ‘1’ through [length - 1]) and clicking on one of the 3C pieces (or 2C pieces) that only has triangular prism stickers.

3) Still looking at this twist type.

4) Mathematically it’s possible to twist a 2D triangle face by 120-degrees. These are the 2D triangle faces where a 3D tetrahedron face and one of the 3D triangular prism faces meet. This includes (a) octahedral sticker(s), as well as two lines (one right side up, one upside down) of triangular prism stickers from each of the other three 3D triangular prism faces.


From: [] On Behalf Of Andrew Gould
Sent: Wednesday, September 29, 2010 22:04
Subject: RE: [MC4D] Re: Tetrahedral prism {3,3}x{}, 3 layers solved

IIIIIII see now. So the triangular prism stickers that are part of 4C pieces can’t be clicked on. I bet you’ll add 120-degree face twists to at least the 2D triangle sides of the rectangular prism stickers. Specifically, on the rectangular prisms of the {3,3}x{} 2 (where you can’t click on any part of any rectangular prism sticker) you could add 180-degree twists when clicking on their 2D rectangular faces and add 120-degree twists to their 2D triangular faces. The idea is inspired by how you did 120 & 90-degree twists to the {4,3,3} 2.

I just imagined having multiple ways the user can choose between 90, 120, and 180 degree twists (seeing as 180-degree twists aren’t possible on the {4,3,3} 2). Possibly keyboard shortcuts like ‘A + Click’, ‘B + Click’, ‘C + Click’, but also possibly (and/or) a third tab on the left side titled ‘twists’. In this, you could also add the 2D twist feature I have wished to see.

1) Speaking of which, last night I verified that some non-3D-face twists are mathematically possible on the {3,3}x{}, like rotating only a 4C piece ALONE by 120 degrees (no other piece moves nor twists).

2) Tonight I have found that on the {3,3}x{} 2 it’s also mathematically possible to twist two 4C pieces alone by 180 degrees (they can’t have the same color tetrahedron sticker–the two 4Cs would end up switching location–if the side length were 3 or greater, then 3C pieces on the line directly between them are also involved). It’s possible without grooves in other stickers. Neither is any extra space needed between stickers.

3) I’m now looking at this one: Take a 3D face that isn’t a tetrahedron (so it’s a bunch of rectangular prism stickers). Take one of the rectangular 2D faces of that (most likely includes the upside down rectangular prisms that are really close to that face). I’ll check if it’s possible to twist this by 180 degrees.


From: [] On Behalf Of Melinda Green
Sent: Wednesday, September 29, 2010 3:36
Subject: Re: [MC4D] Re: Tetrahedral prism {3,3}x{}, 3 layers solved


I’m not suggesting the removal of any records. I’m just asking that solutions to unsupported puzzles be flagged as such because they’re at increased risk of being later invalidated. This case may be perfectly safe as you suggest but there are more reasons why we might not have felt confident enough to support particular puzzles. For example, creating a truly and properly scrambled state is not a trivial thing. It’s very easy to not scramble it enough or to not use enough operators such as to reach all types of states or to make certain types of scrambled states wildly more or less likely.

Thanks for weighing in,

On 9/29/2010 1:22 AM, Galla, Matthew wrote:

There is only one parituclar type of move that you cannot make in 1 click on the {3,3}x{}, 3 puzzle: the rotation of one of the triangular prism faces by 120 degrees. This move can, however, be accomplished in 2 moves (click a 2C piece that faces another triangular prism and then click an edge piece[3C] between 3 triangular prism faces on the same face as the first click)

Therefore, the bug doesn’t lose any states but does potentially change the move count, depending on the solve of course. I think any record made on the current implementation should stay becuase if anything, the bug makes the record worse than it could have been.

Just my two cents :)

-Matt Galla

On Wed, Sep 29, 2010 at 12:29 AM, Melinda Green < > wrote:

I don’t know if there is or is not such a difference. Roice was the one directly supporting the Don’s puzzle creation code so I mostly deferred to his opinions in such matters while I’d veto puzzles with other problems such as infinite loops while scrambling, etc. In general we didn’t include any puzzles that didn’t get the thumbs up from both of us, therefore any puzzles not in that set are considered unsupported. We’re both happy that people explore outside these bounds of the supported set but you’re basically on your own with them in that you risk losing your records if we end up defining a particular puzzle differently from what you solved. It’s also not up to us to prove whether such a change makes for a fundamentally different puzzle. By adding your solution to the wiki’s firsts and shortests, it becomes your responsibility to make sure that it’s accurate according to the puzzle definitions that end up being supported. I suggest that until that time you add an asterisk on the records page with a footnote flagging it as a tentative record. I think that should hold for any more such solutions by anyone. Alternatively, if you can convince Roice that the puzzle is well defined and implemented, then we should add it to the supported list. Of course if you’d like to work on extending the range of supported puzzles, we’d love your help. Just note that Don has a more up-to-date engine that we didn’t know about at the time and the task of incorporating that new engine is our highest priority issue #94 . We’re just not doing any development currently.


On 9/28/2010 10:02 PM, Andrey wrote:

Melinda, Of course, when you show me the twist in new puzzle that can’t be performed in the old one, I’ll agree that this puzzle is different. But now I can’t imagine such twist ))) Andrey — In , Melinda Green <melinda@…> wrote: