Editing Penrose triangle (section)

{{Short description|Impossible object}}
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[[Image:Penrose-dreieck.svg|thumb|upright=1|Penrose triangle]]
The '''Penrose triangle''', also known as the '''Penrose tribar''', the '''impossible tribar''',{{r|pappas}} or the '''impossible triangle''',{{r|brorub}} is a triangular [[impossible object]], an [[optical illusion]] consisting of an object which can be depicted in a perspective drawing. It cannot exist as a solid object in ordinary three-dimensional Euclidean space, although its surface can be embedded isometrically (bent but not stretched) in five-dimensional Euclidean space.<ref name=zeng>{{cite conference
 | last1 = Zeng | first1 = Zhenbing
 | last2 = Xu | first2 = Yaochen
 | last3 = Yang | first3 = Zhengfeng
 | last4 = Li | first4 = Zhi-bin
 | editor1-last = Corless | editor1-first = Robert M.
 | editor2-last = Gerhard | editor2-first = Jürgen
 | editor3-last = Kotsireas | editor3-first = Ilias S.
 | contribution = An isometric embedding of the impossible triangle into the Euclidean space of lowest dimension
 | contribution-url = https://www.maplesoft.com/mapleconference/resources/54_Zeng_IsometricEmbedding_slides.pdf
 | doi = 10.1007/978-3-030-81698-8_29
 | isbn = 9783030816988
 | pages = 438–457
 | publisher = Springer International Publishing
 | title = Maple in Mathematics Education and Research: 4th Maple Conference, MC 2020, Waterloo, Ontario, Canada, November 2–6, 2020, Revised Selected Papers
 | series = Communications in Computer and Information Science
 | year = 2021| volume = 1414
 }}</ref> It was first created by the Swedish artist [[Oscar Reutersvärd]] in 1934.{{r|ernst}} Independently from Reutersvärd, the triangle was devised and popularized in the 1950s by psychiatrist [[Lionel Penrose]] and his son, the mathematician and Nobel Prize laureate [[Roger Penrose]], who described it as "impossibility in its purest form".{{r|penpen}} It is featured prominently in the works of artist [[M. C. Escher]], whose earlier depictions of impossible objects partly inspired it.