Message #2714

From: Jay Berkenbilt <ejb@ql.org>
Subject: Re: [MC4D] Re: Edging closer to a physical 4D puzzle
Date: Mon, 08 Apr 2013 09:56:40 -0400

I wonder if it would be possible to build something that would exist
superimposed upon some kind of frame. It might be a little unwieldy,
but I’m trying to picture a physical structure where you could rotate an
outer face into the center with everything else moving properly. Maybe
someone can figure out how to build something that looks like this
puzzle where it would be possible to push the "front" face into the
center and have all the correct motions happen elsewhere. The invisible
face could be an additional layer distributed around the outsides of the
puzzle. Like many of us, I’ve spent a little time here and there
thinking about how one could build a physical version of this puzzle,
but until now, I never thought about building into a superstructure
rather than having it be self-contained. Self-contained would be much
nicer, but I bet the problem of building it in superstructure would be
more easily solvable and may provide additional insight as to whether a
physical self-contained structure is possible.

–Jay (momentarily emerging from lurker mode)

On 04/06/2013 10:40 PM, Melinda Green wrote:
>
>
> I’ve always assumed that a true physical 4D puzzle would have to offer
> only a small subset of possible twists much like Don and my very first
> version of MC4D just about exactly 25 years ago, come to think of it.
> Happy 25th birthday MC4D!! I think that in that very first
> implementation you could only perform 90 twists and even then only on
> the center face plus along each of the 6 outer faces axis that
> intersects the center face. In other words, only those transforms that
> did not distort any of the pieces during the twists.
>
> For a true physical 4D cube you don’t even need those outer 6 twists.
> So long as you first rotate your face-of-interest into the center, you
> can then perform all the twists you like on that face without
> distortions. I just have no idea what sort of construction would allow
> the rotations. Maybe something involving a squishy material like latex
> or something that can stretch a lot without breaking. I can almost
> imagine some latex webbing that stretches between the arms of the
> Roadblock faces. I think I’ll ask Oskar to think about this problem
> too. If anyone can figure this out, he seems like the one.
>
> -Melinda
>
> On 4/6/2013 2:09 PM, Ray Zhao wrote:
>> No wonder I thought I’ve seen something similar before (didn’t think
>> of the 2^4 when I first saw Oskar’s puzzle)…There just needs to be
>> some eighth cell and the 2x2x2s still have to be able to rotate
>> individually in all 3 axes. That’ll take a while =P
>> When a physical 4D puzzle is made, will it have the
>> Schlegel-diagram-like cell-centered view, since if that’s the case
>> then it will be hard to turn the "inner/far" cell…
>
>