Talk:Penrose triangle

message: 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)
replies: text: This seems to be taking the discussion further afield.  Penrose isn't credited with inventing impossible objects, just the tribar.  Those images you mention are obviously related, but are not the tribar itself.  Some of the appeal of the tribar seems to be from the simplicity of the triangular shape.  Reutersvard should probably also be credited, but it's interesting to note that his "Impossible triangle" does have substantial difference with the tribar as usually depicted nowadays: it is made of a series of cubes rather than three beams.  I suspect the reason Penrose's depiction is more often seen is that it is more visually striking.  --C S (talk) 09:44, 9 March 2009 (UTC)
thread_title: Priority

message: 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)
replies: text: 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)
thread_title: Image not showing up

message: 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)
thread_title:  Change main title to "Tribar"? 

message: this is a better impossible triangl picture!Image:Imposible shape 3
Here is a moving image of a Penrose Triangle: https://www.facebook.com/100009344523684/videos/764913091656665  — Preceding unsigned comment added by 69.121.228.77 (talk) 19:29, 13 December 2023 (UTC)
thread_title:  better picture 

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

message: 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.
Image:Penrose_square.svg|Penrose square
Image:Penrose_pentagon.svg|Penrose pentagon
Image:Penrose_hexagon.svg|Penrose hexagon
Image:Penrose_octagon.svg|Penrose octagon
If there are no reasonable objections in the next week I will go ahead and replace the current images. 
Trilink 02:49, 2 December 2007 (UTC)
replies: text: *Looks great. Well done - Gobeirne (talk) 03:48, 10 December 2007 (UTC)
thread_title:  Proposed image change. 

message: There is no explanation offered for the Austrian impossible tribar sculpture in the article, and it is rather confusing tot ry to figure out how it exists. It does not appear to be disjointed, and I examined the image provided in the "links" section as well (which is from a slightly different angle). There really should be something in the way of clarifying how that particular illusion works. 216.82.142.13 (talk) 19:45, 18 March 2009 (UTC)
replies: text: Check out the description on the image's page at :Image:ImpossibleTriangleEastPerth_edit_gobeirne.jpg. Doctorfluffy (robe and wizard hat) 20:05, 18 March 2009 (UTC)
replies: text: The question is not answered. "Austrian" and "Australian" relate to two different sculptures in two separate continents. Snezzy (talk) 16:35, 29 August 2011 (UTC)
thread_title:  Austrian impossible tribar sculpture - explanation? 

message: How can the Penrose triangle be inspired by M. C. Escher, when it was created in 1934, while Escher's first impossible print was published in 1937? -- Jsdo1980 (talk) 11:20, 17 May 2009 (UTC)
replies: text: Two people independently "discovered" it at different times. The latter of which was inspired by Escher. Doctorfluffy (robe and wizard hat) 16:51, 17 May 2009 (UTC)

text: Build this then: :Image:Escher Waterfall.jpg --TheSane (talk) 10:21, 19 February 2011 (UTC)
thread_title:  Inspired by M. C. Escher? 

message: It seems that Ulrich Schwanitz the designer of the 3D penrose pictured, DMCAed the thingiverse link calling it an infringement of his copyright. 
List of things I found:
* Ulrich is German 
:this search proves nothing. In the thingiverse comments there is a post about Mr. Schwanitz beeing from the Netherlands, which is possible but again unproven. IMHO it doesnt matter, though. --0x6d64 (talk) 10:49, 19 February 2011 (UTC)
replies: text: Use your favorite firefox plugin to search caches. --0x6d64 (talk) 10:49, 19 February 2011 (UTC)

text: I don't suppose any of you thingiverse folks noticed that he put "The design files for this model have now been released to the public domain" on his page, linking to the design files? He's given up copyright on it. How does someone file a DMCA takedown notice on an item they've released to the public domain? Permalink at http://www.webcitation.org/5wfT4qTPT 12.186.80.1 (talk) 17:35, 21 February 2011 (UTC)
thread_title:   Copyright violation 

message: It's possible,by is optical ilussion and cappable to build.  — Preceding unsigned comment added by 188.26.250.159 (talk) 18:48, 21 January 2014 (UTC)
thread_title: Experience

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thread_title:  External links modified (January 2018) 

message: The image "A 3D-printed version of the Reutersvard Triangle illusion" appears to me to have been heavily doctored. A close look suggests a hand-drawn Reutersvard triangle may be Photoshopped into a photo of a posed hand holding something else. Can a reliable source be found to back up the "3D-printed" claim? Shadowing and exposure, particularly where the triangle meets the hand, are rather incongruous with the rest of the photo. Public fascination with 3-D printers, combined with public ignorance about their limitations and capabilities, would seem to create a fertile environment to hoax folks into believing 3-D printers produce impossible objects. There was no way I could verify the caption's claim that the triangle in the image is a 3-D printed object because I couldn't find any other images of it from the same author besides the heavily posed picture someone included in this article (and others?)106.1.65.224 (talk) 00:13, 27 April 2018 (UTC)
thread_title:  Possible graffiti and/or hoax image