POV-Ray : Newsgroups : povray.binaries.images : penrose tiles and sphere(180K?) Server Time
1 Oct 2024 18:32:01 EDT (-0400)
  penrose tiles and sphere(180K?) (Message 1 to 10 of 12)  
Goto Latest 10 Messages Next 2 Messages >>>
From: Quadhall
Subject: penrose tiles and sphere(180K?)
Date: 16 Jul 2000 19:42:19
Message: <3972485b@news.povray.org>
a work in progress.......
Quadhall


Post a reply to this message


Attachments:
Download 'a7.jpg' (166 KB)

Preview of image 'a7.jpg'
a7.jpg


 

From: John VanSickle
Subject: Re: penrose tiles and sphere(180K?)
Date: 16 Jul 2000 21:07:55
Message: <39725C85.4B510B8E@erols.com>
Quadhall wrote:
> 
> a work in progress.......

A pedantic nitpick, but while the red and blue tiles are shaped like
those of a Penrose tiling, they are not arranged in the Penrose pattern.

Regards,
John
-- 
ICQ: 46085459


Post a reply to this message

From: Anton Sherwood
Subject: Re: penrose tiles and sphere(180K?)
Date: 17 Jul 2000 01:42:36
Message: <39729E51.289ED5@pobox.com>
John VanSickle wrote:
> A pedantic nitpick, but while the red and blue tiles are shaped like
> those of a Penrose tiling, they are not arranged in the Penrose pattern.

Tangentially I wonder whether it's possible to cover a sphere with tiles
topologically equivalent to Penrose's.

-- 
Anton Sherwood  --  br0### [at] p0b0xcom  --  http://ogre.nu


Post a reply to this message

From: Christoph Hormann
Subject: Re: penrose tiles and sphere(180K?)
Date: 17 Jul 2000 03:16:22
Message: <3972B2C7.86DD4606@schunter.etc.tu-bs.de>
Anton Sherwood wrote:
> 
[...]
> Tangentially I wonder whether it's possible to cover a sphere with tiles
> topologically equivalent to Penrose's.
> 

I'm no expert in spherical geometry, but that could be possible if you would
distort the single tiles a bit (change angles).  The structure of real penrose
tiling is quite irregular, so this could be quite difficult... you will probably
have to work with variable distortion.

I could think of a program where the tiling grows and angles are adaptively
modified to follow a sphere's shape.  I'm not sure if that works, probably
things would not fit together in the end.  

Christoph

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/


Post a reply to this message

From: Jan Walzer
Subject: Re: penrose tiles and sphere(180K?)
Date: 17 Jul 2000 16:37:14
Message: <39736e7a@news.povray.org>
I'm sure there must be a way to cover a sphere, but your pattern

too. But You surely know that you can aproximate a sphere by n
equal-sided triangles, where n are some discrete numbers...

I don't know if it will work, to take 2 of these triangles
together, but maybe you can get your' penrose tiling this way to
the sphere ...

hmm ... quite hard to explain, hope you know what I mean...

--

 ,',    Jan Walzer      \V/  http://wa.lzer.net     ,',
',','   student of      >|<  mailto:jan### [at] lzernet ',','
  '   ComputerScience   /A\  +49-177-7403863         '


Post a reply to this message

From: Quadhall
Subject: Re: penrose tiles and sphere(180K?)
Date: 17 Jul 2000 22:06:24
Message: <3973bba0@news.povray.org>
Thanks for pointing that out--->I won't change this image as a result, but
perhaps I will incorportate a true Penrose tiling in a future image.  Oh,
and nitpick away, it helps me to learn and stay humble (not that I have much
reason not to be humble).  Thanks again.


John VanSickle wrote in message <39725C85.4B510B8E@erols.com>...
>Quadhall wrote:
>>
>> a work in progress.......
>
>A pedantic nitpick, but while the red and blue tiles are shaped like
>those of a Penrose tiling, they are not arranged in the Penrose pattern.
>
>Regards,
>John
>--
>ICQ: 46085459


Post a reply to this message

From: Jamie Davison
Subject: Re: penrose tiles and sphere(180K?)
Date: 18 Jul 2000 14:41:46
Message: <MPG.13dd6a3c415ceeea98974f@news.povray.org>
On Sun, 16 Jul 2000 21:08:21 -0400, John VanSickle wrote...
> Quadhall wrote:
> > 
> > a work in progress.......
> 
> A pedantic nitpick, but while the red and blue tiles are shaped like
> those of a Penrose tiling, they are not arranged in the Penrose pattern.

I thought that the whole point of penrose tiling was that there *was* no 
pattern, that you could fling the tiles together almost randomly and 
still get them to tesselate...

I could easily be wrong though.

Bye for now,
     Jamie.


Post a reply to this message

From: Christoph Hormann
Subject: Re: penrose tiles and sphere(180K?)
Date: 18 Jul 2000 14:57:53
Message: <3974A8B2.CB19171E@schunter.etc.tu-bs.de>
Jamie Davison wrote:
> 
[...]
> 
> I thought that the whole point of penrose tiling was that there *was* no
> pattern, that you could fling the tiles together almost randomly and
> still get them to tesselate...
> 
> I could easily be wrong though.
> 
> Bye for now,
>      Jamie.

IIRC, penrose tilings have a nonperiodic structure, but they are based on very
simple rules, for example fractint describes penrose tiling with the following
L-System:

Penrose1 {
  Angle 10
  Axiom +WF--XF---YF--ZF
  W=YF++ZF----XF[-YF----WF]++
  X=+YF--ZF[---WF--XF]+
  Y=-WF++XF[+++YF++ZF]-
  Z=--YF++++WF[+ZF++++XF]--XF
  F=
}

So there is only one unique penrose tiling, and changing any element, even if
the tiling stays complete, would no more be a real penrose :-)

Christoph

--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/


Post a reply to this message

From: Anton Sherwood
Subject: Re: penrose tiles and sphere(180K?)
Date: 28 Jul 2000 23:20:29
Message: <39824F0E.1CEDDA44@pobox.com>
Jamie Davison wrote:
> I thought that the whole point of penrose tiling was that there *was* no
> pattern, that you could fling the tiles together almost randomly and
> still get them to tesselate...

It's not periodic, but (iirc) every infinite Penrose tiling contains
every finite Penrose tiling -- *because* it is not periodic.

-- 
Anton Sherwood  --  br0### [at] p0b0xcom  --  http://ogre.nu/


Post a reply to this message

From: Jerome M  Berger
Subject: Re: penrose tiles and sphere(180K?)
Date: 31 Jul 2000 08:07:39
Message: <39856C06.30BF69@tapasmail.net>
John VanSickle wrote:
> 
> Quadhall wrote:
> >
> > a work in progress.......
> 
> A pedantic nitpick, but while the red and blue tiles are shaped like
> those of a Penrose tiling, they are not arranged in the Penrose pattern.
> 
	Well, according to this page:
http://mathworld.wolfram.com/PenroseTiles.html they're not
even shaped like a Penrose tiling's tiles...

		Jerome
-- 

* Doctor Jekyll had something * mailto:ber### [at] inamecom
* to Hyde...                  * http://www.enst.fr/~jberger
*******************************


Post a reply to this message

Goto Latest 10 Messages Next 2 Messages >>>

Copyright 2003-2023 Persistence of Vision Raytracer Pty. Ltd.