Mathematics of rigidity | Nonconvex polyhedra

Steffen's polyhedron

In geometry, Steffen's polyhedron is a flexible polyhedron discovered (in 1978) by and named after . It is based on the Bricard octahedron, but unlike the Bricard octahedron its surface does not cross itself. With nine vertices, 21 edges, and 14 triangular faces, it is the simplest possible non-crossing flexible polyhedron. Its faces can be decomposed into three subsets: two six-triangle-patches from a Bricard octahedron, and two more triangles (the central two triangles of the net shown in the illustration) that link these patches together. It obeys the strong bellows conjecture, meaning that (like the Bricard octahedron on which it is based) its Dehn invariant stays constant as it flexes. (Wikipedia).

Steffen's polyhedron
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Class 16: Vertex & Orthogonal Unfolding

MIT 6.849 Geometric Folding Algorithms: Linkages, Origami, Polyhedra, Fall 2012 View the complete course: http://ocw.mit.edu/6-849F12 Instructor: Erik Demaine This class reviews covers topologically convex vertex-ununfoldable cases and unfolding for orthogonal polyhedra, including the app

From playlist MIT 6.849 Geometric Folding Algorithms, Fall 2012

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Steffen Borgwardt: The role of partition polytopes in data analysis

The field of optimization, and polyhedral theory in particular, provides a powerful point of view on common tasks in data analysis. In this talk, we highlight the role of the so-called partition polytopes and their studies in clustering and classification. The geometric properties of parti

From playlist Workshop: Tropical geometry and the geometry of linear programming

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Regular polyhedra

This shows a 3d print of a mathematical sculpture I produced using shapeways.com. This model is available at http://shpws.me/q0PF.

From playlist 3D printing

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What are four types of polygons

👉 Learn about polygons and how to classify them. A polygon is a plane shape bounded by a finite chain of straight lines. A polygon can be concave or convex and it can also be regular or irregular. A concave polygon is a polygon in which at least one of its interior angles is greater than 1

From playlist Classify Polygons

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What is the definition of a regular polygon and how do you find the interior angles

👉 Learn about polygons and how to classify them. A polygon is a plane shape bounded by a finite chain of straight lines. A polygon can be concave or convex and it can also be regular or irregular. A concave polygon is a polygon in which at least one of its interior angles is greater than 1

From playlist Classify Polygons

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What are the names of different types of polygons based on the number of sides

👉 Learn about polygons and how to classify them. A polygon is a plane shape bounded by a finite chain of straight lines. A polygon can be concave or convex and it can also be regular or irregular. A concave polygon is a polygon in which at least one of its interior angles is greater than 1

From playlist Classify Polygons

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What is the difference between convex and concave polygons

👉 Learn about polygons and how to classify them. A polygon is a plane shape bounded by a finite chain of straight lines. A polygon can be concave or convex and it can also be regular or irregular. A concave polygon is a polygon in which at least one of its interior angles is greater than 1

From playlist Classify Polygons

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What is a net

👉 Learn about polygons and how to classify them. A polygon is a plane shape bounded by a finite chain of straight lines. A polygon can be concave or convex and it can also be regular or irregular. A concave polygon is a polygon in which at least one of its interior angles is greater than 1

From playlist Classify Polygons

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What is the difference between convex and concave

👉 Learn about polygons and how to classify them. A polygon is a plane shape bounded by a finite chain of straight lines. A polygon can be concave or convex and it can also be regular or irregular. A concave polygon is a polygon in which at least one of its interior angles is greater than 1

From playlist Classify Polygons

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Sketch a net from a 3D figure

👉 Learn about polygons and how to classify them. A polygon is a plane shape bounded by a finite chain of straight lines. A polygon can be concave or convex and it can also be regular or irregular. A concave polygon is a polygon in which at least one of its interior angles is greater than 1

From playlist Classify Polygons

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Bistability in the stabilized Kuramoto-Sivashinsky equation

The Kuramoto-Sivashinsky equation, with its range stabilized based on advice from Steffen Richters. Pattern created by Dan Wills. Video made in Ready: https://github.com/GollyGang/ready The equation is: da/dt = 0.2 * gradient_magnitude_squared(a) - bilaplacian(a) - laplacian(a) - 0.05 *

From playlist Ready

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ETech 2009 - Alex Steffen, World Changing

One Question for Alex Steffen at the 2009 O'Reilly Emerging Technology Conference: How might we redefine the American life to solve big problems?

From playlist ETech 2009

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Live CEOing Ep 186: Polyhedra in Wolfram Language

Watch Stephen Wolfram and teams of developers in a live, working, language design meeting. This episode is about Polyhedra in the Wolfram Language.

From playlist Behind the Scenes in Real-Life Software Design

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Hermitian and Non-Hermitian Laplacians and Wave Equaions by Andrey shafarevich

Non-Hermitian Physics - PHHQP XVIII DATE: 04 June 2018 to 13 June 2018 VENUE:Ramanujan Lecture Hall, ICTS Bangalore Non-Hermitian Physics-"Pseudo-Hermitian Hamiltonians in Quantum Physics (PHHQP) XVIII" is the 18th meeting in the series that is being held over the years in Quantum Phys

From playlist Non-Hermitian Physics - PHHQP XVIII

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Ben Smith: Face structures of tropical polyhedra

Many combinatorial algorithms arise from the interplay between faces of ordinary polyhedra, therefore tropicalizing these algorithms should rely on the face structure of tropical polyhedra. While they have many nice combinatorial properties, the classical definition of a face is flawed whe

From playlist Workshop: Tropical geometry and the geometry of linear programming

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Introduction Polyhedra Using Euler's Formula

This video introduces polyhedra and how every convex polyhedron can be represented as a planar graph. mathispower4u.com

From playlist Graph Theory (Discrete Math)

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Interactivity: Building and App in 60 Seconds

With the Wolfram Language and Mathematica, you really can build a useful, interactive app for exploring ideas in just 60 seconds. Starting with the 60-second app, this talk covers the ins and outs of the Wolfram Language function Manipulate, the key to instantly interactive interfaces. You

From playlist Geek Out with Wolfram Virtual Workshop 2014

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What is the difference between a regular and irregular polygon

👉 Learn about polygons and how to classify them. A polygon is a plane shape bounded by a finite chain of straight lines. A polygon can be concave or convex and it can also be regular or irregular. A concave polygon is a polygon in which at least one of its interior angles is greater than 1

From playlist Classify Polygons

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Classify a polygon as concave, convex, regular or irregular ex 1

👉 Learn about polygons and how to classify them. A polygon is a plane shape bounded by a finite chain of straight lines. A polygon can be concave or convex and it can also be regular or irregular. A concave polygon is a polygon in which at least one of its interior angles is greater than 1

From playlist Classify Polygons

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Live CEOing Ep 173: Geometry in Wolfram Language

Watch Stephen Wolfram and teams of developers in a live, working, language design meeting. This episode is about Geometry in the Wolfram Language.

From playlist Behind the Scenes in Real-Life Software Design

Related pages

Dehn invariant | Geometry | Bricard octahedron | Flexible polyhedron