Message #1899

From: Nan Ma <>
Subject: Re: [MC4D] Re: yet more new puzzles and a prize
Date: Mon, 07 Nov 2011 00:56:39 -0800

Hi Roice,

About the Klein quartic, I’m curious if the vertex turning and edge turning
{7,3} can be made. They have less colors than the {3,7} counterparts. So it
should be easier to find pieces on them. Thanks.


On Sun, Nov 6, 2011 at 4:42 PM, Roice Nelson <> wrote:

> **
> No worries at all - I had just wanted to let you know rotation was
> available.
> It looks like Don has hardcoded the motion model (which he did
> independently of the hyperbolic geometry model), and not provided a key
> toggle to switch it. My apologies for not mentioning that earlier. To see
> the other models, you’d need to recompile his applet after altering the
> code. In the version I have downloaded, the code is around line 1374 of
> the file HyperbolicApplet.prejava file, and looks like this:
> //int motionModel = TRACKBALL;
> //int motionModel = DRAG_GEODESIC;
> //int motionModel = DRAG_NONPRECESSING;
> You could change what is commented to try the other models. Getting a
> setup to recompile would probably take some effort though.
> With regards to hyperbolic geometry models, I’ve played with a few of
> these in MagicTile, but I haven’t yet made the controls work for them. I
> just uploaded a couple pictures… some puzzles in the Klein model, and one
> pasted on the pseudosphere <>.
> The Klein model may become my favorite view when solving puzzles. It has
> a very spherical feel to it, due to circles getting squashed towards the
> edges, and magnifies pieces near the center. I don’t think the
> pseudosphere ends up being a very workable view, since you can’t show a
> large percentage of the hyperbolic plane on it at once.
> seeya,
> Roice
> On Sat, Nov 5, 2011 at 4:38 PM, schuma <> wrote:
>> Sorry for not noticing the middle mouse drag function.
>> In Don’s applet I don’t know how to change to another motion model.
>> Poincare model/Klein model behave in the same way. I’m not surprised by
>> anti-procession because rolling a ball is anti-procession. Since sphere and
>> hyperbolic plane are opposite, it’s natural to see procession in the
>> hyperbolic plane. But I don’t know how to see anti-procession in hyperbolic.
>> Nan
>> — In, Roice Nelson <roice3@…> wrote:
>> >
>> > Middle-mouse drag will do a rotation for you (or on a laptop, left+right
>> > drag at the same time).
>> >
>> > I find the noncommutative panning in spherical/hyperbolic spaces really
>> > neat too (doesn’t happen for Euclidean space, so middle-mouse control is
>> > required there). The code for Don’s hyperbolic tesselations
>> > applet<>was super helpful
>> > in understanding and implementing this. Internally, you
>> > can see he played with a few different motion models, some of which
>> > anti-precess rather than precess! That is, dragging clockwise results
>> in a
>> > counterclockwise rotation of the space. I found that I liked the one he
>> > settled on for his applet the best too, though it’d be nice to add in
>> some
>> > of the others as an option.
>> >
>> > seeya,
>> > Roice