In geometry, the small retrosnub icosicosidodecahedron (also known as a retrosnub disicosidodecahedron, small inverted retrosnub icosicosidodecahedron, or retroholosnub icosahedron) is a nonconvex uniform polyhedron, indexed as U72. It has 112 faces (100 triangles and 12 pentagrams), 180 edges, and 60 vertices. It is given a Schläfli symbol sr{⁵/₃,³/₂} The 40 non-snub triangular faces form 20 coplanar pairs, forming star hexagons that are not quite regular. Unlike most snub polyhedra, it has reflection symmetries. George Olshevsky nicknamed it the yog-sothoth (after the Cthulhu Mythos deity). (Wikipedia).
How to Construct an Icosahedron
How the greeks constructed the icosahedron. Source: Euclids Elements Book 13, Proposition 16. In geometry, a regular icosahedron is a convex polyhedron with 20 faces, 30 edges and 12 vertices. It is one of the five Platonic solids, and the one with the most faces. https://www.etsy.com/lis
From playlist Platonic Solids
The remarkable Platonic solids II: symmetry | Universal Hyperbolic Geometry 48 | NJ Wildberger
We look at the symmetries of the Platonic solids, starting here with rigid motions, which are essentially rotations about fixed axes. We use the normalization of angle whereby one full turn has the value one, and also connect the number of rigid motions with the number of directed edges.
From playlist Universal Hyperbolic Geometry
👉 Learn the essential definitions of triangles. A triangle is a polygon with three sides. Triangles are classified on the basis of their angles or on the basis of their side lengths. The classification of triangles on the bases of their angles are: acute, right and obtuse triangles. The cl
From playlist Types of Triangles and Their Properties
👉 Learn the essential definitions of triangles. A triangle is a polygon with three sides. Triangles are classified on the basis of their angles or on the basis of their side lengths. The classification of triangles on the bases of their angles are: acute, right and obtuse triangles. The cl
From playlist Types of Triangles and Their Properties
Canonical structures inside the Platonic solids III | Universal Hyperbolic Geometry 51
The dodecahedron is surely one of the truly great mathematical objects---revered by the ancient Greeks, Kepler, and many mathematicians since. Its symmetries are particularly rich, and in this video we look at how to see the five-fold and six-fold symmetries of this object via internal str
From playlist Universal Hyperbolic Geometry
What is a perpendicular bisector
👉 Learn the essential definitions of triangles. A triangle is a polygon with three sides. Triangles are classified on the basis of their angles or on the basis of their side lengths. The classification of triangles on the bases of their angles are: acute, right and obtuse triangles. The cl
From playlist Types of Triangles and Their Properties
👉 Learn the essential definitions of triangles. A triangle is a polygon with three sides. Triangles are classified on the basis of their angles or on the basis of their side lengths. The classification of triangles on the bases of their angles are: acute, right and obtuse triangles. The cl
From playlist Types of Triangles and Their Properties
What is an equilateral triangle
👉 Learn the essential definitions of triangles. A triangle is a polygon with three sides. Triangles are classified on the basis of their angles or on the basis of their side lengths. The classification of triangles on the bases of their angles are: acute, right and obtuse triangles. The cl
From playlist Types of Triangles and Their Properties
👉 Learn the essential definitions of triangles. A triangle is a polygon with three sides. Triangles are classified on the basis of their angles or on the basis of their side lengths. The classification of triangles on the bases of their angles are: acute, right and obtuse triangles. The cl
From playlist Types of Triangles and Their Properties
Scotland Ruby 2011 - What Ruby Can Learn From Smalltalk
by: Steven Baker Smalltalk is one of the forefathers of Object Oriented programming, and has a long history of being used in the field. One of the quiet players, many have heard of Smalltalk without having worked with it, but Smalltalk is indispensable in many industries including insuran
From playlist Scotland Ruby 2011
MountainWest RubyConf 2014 - But Really, You Should Learn Smalltalk
By Noel Rappin Smalltalk has mystique. We talk about it more than we use it. It seems like it should be so similar to Ruby. It has similar Object-Oriented structures, it even has blocks. But everything is so slightly different, from the programming environment, to the 1-based arrays, to t
From playlist MWRC 2014
Lec 11 | MIT 6.002 Circuits and Electronics, Spring 2007
Small signal circuits View the complete course: http://ocw.mit.edu/6-002S07 License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
From playlist MIT 6.002 Circuits and Electronics, Spring 2007
PrepTest 5 Game 2: A Grouping Game with No Groups // Logic Games [#18] [LSAT Analytical Reasoning]
We've seen a grouping game with no elements before (https://youtu.be/5U0mlFdeZ6c), so how about a grouping game with no groups. This is the second game of the June 1992 LSAT games section. I suppose it's not quite right to say it has no groups. The way I diagram it is as if there are three
From playlist LSAT Games
Lec 7 | MIT 6.002 Circuits and Electronics, Spring 2007
Incremental analysis View the complete course: http://ocw.mit.edu/6-002S07 License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
From playlist MIT 6.002 Circuits and Electronics, Spring 2007
A tale of two dynamos: turbulent large-scale and small-scale dynamos by Pallavi Bhat
Abstract: Coherent magnetic fields are ubiquitous in the universe as in the Sun, stars, galaxies and galaxy clusters. The theory of turbulent dynamos is the leading paradigm to understand the origin of these magnetic fields. A particularly generic process in turbulent astrophysical system
From playlist ICTS Colloquia
Grigorios Paouris: Non-Asymptotic results for singular values of Gaussian matrix products
I will discuss non-asymptotic results for the singular values of products of Gaussian matrices. In particular, I will discuss the rate of convergence of the empirical measure to the triangular law and discuss quantitive results on asymptotic normality of Lyapunov exponents. The talk is bas
From playlist Workshop: High dimensional measures: geometric and probabilistic aspects
Emily Riehl: On the ∞-topos semantics of homotopy type theory: The simplicial model of...- Lecture 2
HYBRID EVENT Recorded during the meeting "Logic and Interactions" the February 22, 2022 by the Centre International de Rencontres Mathématiques (Marseille, France) Filmmaker: Guillaume Hennenfent Find this video and other talks given by worldwide mathematicians on CIRM's Audiovisual M
From playlist Topology
Ruby Conference 2008 - Ruby Persistence in MagLev
By: Bob Walker, Allan Ottis Help us caption & translate this video! http://amara.org/v/GH3J/
From playlist Ruby Conference 2008
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