Talk:Penrose triangle

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1 Priority
2 Image not showing up
3 Change main title to "Tribar"?
4 better picture
5 better picture
6 Possible?
7 Proposed image change.

[edit] Priority

I find it difficult to believe that this object was first devised by Roger Penrose. I would bet any of the classical Masters must have been aware of it, or at least, Projective Geometers, etc... To the point: the claim that Penrose was the inventor comes from what source? Thanks. Pfortuny 07:20, 13 Apr 2004 (UTC)

Lionel and Roger Penrose published a letter in the British Journal of Psychology regarding the triangle (the article is correct though, as it was Roger Penrose who came up with it). Whether they were the first inventors of it or not is irrelevent - if anyone else came up with it before, either they didn't bother to make others aware of its existence, or that knowledge was lost again. Average Earthman 07:37, 1 Jun 2004 (UTC)

I've now found the cite - Penrose, Lionel and Roger Penrose, "Impossible objects: A Special Type of Visual Illusion," British Journal of Psychology, vol. 49, 1958, pp. 31-33
OK, you piqued my interest, so I did a more thorough search on the web - and I've now found someone who came up with the triangle before them - Swedish artist Oscar Reutersvard, who drew 'impossible figures' in Japanese perspective. Apparently, neither Escher nor Penrose were aware of his work. Average Earthman 08:16, 1 Jun 2004 (UTC)
Reutersvald made a career out of drawing these sorts of things, and published huge numbers of them, and if more modern mathematical researchers didn't know about it, then maybe they should have asked a graphic designer friend or someone who'd done a "history of art" course about it. As for popularisation, "impossible" artworks had been hanging in museums for centuries before Penrose "popularised" the tribar by publishing a piece on it in that influential mass-media cultural touchstone ... the British Journal of Psychology (??). Ahem. ErkDemon 23:24, 20 June 2007 (UTC)

We may be able to give the Penroses credit for identifying these shapes, and for trying to give them an academic classification, and popularising them amongst mathematicans, but these sorts of things had already been hanging in museums for rather a long time. Try Googling for an image of "The Magpie on the Gallows" by Pieter Brueghel or Apolinère Enameled by Marcel Duchamp. These are not exactly unknown artists. ErkDemon 23:24, 20 June 2007 (UTC)

[edit] Image not showing up

At the bottom of the page the image for the Penrose rectangle is not showing up for me. Anyone know the problem? --Captain538[talk] 01:01, 12 October 2006 (UTC)

Dunno. But Wikipedia is not an instruction manual, so intructions to draw it should probably be ommited. Although, I do like your idea. We could probably put it to good use somewhere, I just don't know where that is. --172.191.129.64 01:01, 13 October 2006 (UTC)

[edit] Change main title to "Tribar"?

Ive been seeing these figures in books for years, and I don't think I've ever seen them referred to as Penrose triangles: they've always been referred to as "tribars", or "impossible tribars".

It may be that these things are referred to as "Penrose" objects within the mathematical community, but I really don't think its the popular name for them (although some Penrose fans do seem to be fond of trying to get things named after their guy).

Rather than getting into disputes over "Penrose triangles" vs "Reutersvärd triangles", couldn't we just refer to the things as "tribars" and have done with it? A quick unscientific Google poll for hits for "tribar" vs "Penrose triangle" suggests a ratio of about 65,000 vs. 10,000.

"Penrose triangle" is also slightly confusing because although the thing is basically triangular it isn't a literal triangle, and because Penrose is now associated with Penrose tiling, which he did invent, and which does tend to involve real triangles. Make "tribar" the primary name and "P-t" a secondary name, but keep all the Penrose info, and the Penrose polygons as good supplementary info? ErkDemon 01:02, 21 June 2007 (UTC)

[edit] better picture

this is a better impossible triangl picture!Image:Imposible shape 3

[edit] better picture

this is a better impossible triangl picture!Image:Imposible shape 3.jpg

[edit] Possible?

http://www.coolopticalillusions.com/build-an-impossible-triangle.htm Mwv2 05:32, 29 October 2007 (UTC)

[edit] Proposed image change.

I really found the Penrose polygons interesting, but I thought the images were a bit confusing. I thought the effect would be much clearer if a few of the lines removed and the "sides" color coded (as in Image:Penrose triangle.svg), so I made svg images based on the current images, but with those changes. I also changed the rectangle to a square because I felt a regular polygon would fit in with the other examples better, and rotated it 45 degrees because I felt that increased the resemblance to Image:Penrose triangle.svg. I used the same licenses for each as on the current images.