This is great! I was thinking: is it possible to make "u" unfold and "f" fold, so we don't have to keep hitting the button to switch? Or if you prefer, make click fold and shift-click unfold? Or left click fold and right click unfold? Even though I mostly use vim these days, I'm not a big fan of modality . . . -tom On Sun, Oct 25, 2020 at 7:54 AM Christian Lawson-Perfect < christianperfect@gmail.com> wrote:
A little update: I've changed my interactive thing so that you have to click once to select a line, then again to select a side to fold onto. I've also made it keep track of moves and store them in the URL, so you can share solutions more easily. Finally, I changed "unfold" so it only folds the points on one side.
Allan, is it OK if I share this outside math-fun, crediting you with the idea?
On Fri, 23 Oct 2020 at 07:05, Christian Lawson-Perfect < christianperfect@gmail.com> wrote:
Christian: how big is the original Elm program?
The code is at https://github.com/christianp/gaussian-origami. It's just over 400 lines of elm at the moment.
I really really should be doing my actual job, but I think it would help matters to be able to share links to sequences of moves, so I'll try to add that.
On Thu, 22 Oct 2020, 21:39 Allan Wechsler, <acwacw@gmail.com> wrote:
I think Tom's 3-step solution is incorrect, and produces i as well as the desired 3 points. But this could be interpreted as a difference of opinion about what the "unfold" operation does. I imagined "unfold" as the union of the original set and its reflection around the crease. Christian's web app agrees with me.
Christian: how big is the original Elm program?
On Thu, Oct 22, 2020 at 4:16 PM Tom Karzes <karzes@sonic.net> wrote:
Nice. I have a different 3-fold solution:
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1. Unfold 0 to 2+2i 2. Fold 2+2i to 2+i 3. Unfold 2+i to 2
Tom
Allan Wechsler writes:
Tom Rokicki builds 0, 2, 2+i from 0 in four steps. It's easy to prove that it takes at least three steps ... and I just realized that three steps can indeed be done. So there's a certain sort of "code golf" that can be played with this sort of puzzle. Answer below.
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1. Unfold 0 to 2 2. Unfold 0 to 2+2i (2 is on the crease) 3. Fold 2+2i to 2+i.
On Thu, Oct 22, 2020 at 3:12 PM Tomas Rokicki <rokicki@gmail.com> wrote:
Spoiler space.
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Unfold (0,0) to (2,0) Unfold (2,0) to (3,0) (creates (5,0) as well) Fold (5,0) to (3,0) Fold (3,0) to (2,i).
This is just my raster strategy, only using a spiral instead of a raster.
-tom
On Thu, Oct 22, 2020 at 10:50 AM Allan Wechsler < acwacw@gmail.com> wrote:
> Okay, two things: a comment about notation, and a starting puzzle. > > I mentioned that I could do 0 -> 0, 2+i in two moves. Here is my solution, > presented as a way to suggest an unambiguous and fairly terse notation. > > 1. Unfold 0 to 2+2i. > 2. Fold 2+2i to 2+i. > > In each case the operation is performed so as to put a copy of the first > point onto the second. This specifies the crease axis unambiguously. Some > moves are illegal, so it isn't acceptable to say "unfold 0 to 2+i", because > there is no permissible crease that does that. The second point has to be a > queen's move from the first. > > Now the puzzle, the simplest one I haven't been able to do yet: > > From {0}, construct {0, 2, 2+i}. > >
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