GeometryFact's profile picture. Geometric miscellany, from ancient to modern. On temporary hiatus; publishes occasionally. Curated by @Thalesdisciple.

Geometry Fact

@GeometryFact

Geometric miscellany, from ancient to modern. On temporary hiatus; publishes occasionally. Curated by @Thalesdisciple.

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“Geometry is unique and eternal, and it shines in the mind of God.” —Johannes Kepler, Conversation with Galileo’s Sidereal Messenger


Geometry Fact reposted

Proofs of Nothing 🖍📐


Geometry Fact reposted

The AMS, jointly with the MAA, is pleased to offer their book, Living Proof: Stories of Resilience Along the Mathematical Journey, as a free PDF download. ams.org/about-us/Livin…


Geometry Fact reposted

If an infinite set of points in the plane determines only integer distances, then all the points lie on a straight line. -- Paul Erdös


Geometry Fact reposted

Book illustration: the 21 types of vertices that can be formed by regular polygons. Those in a generate the regular tessellations, b semi-regular, c tessellations with more than one type of vertex. There are no tilings of regular polygons that contain the vertices in area d.

RobFathauerArt's tweet image. Book illustration: the 21 types of vertices that can be formed by regular polygons. Those in a generate the regular tessellations, b semi-regular, c tessellations with more than one type of vertex. There are no tilings of regular polygons that contain the vertices in area d.

Geometry Fact reposted

I’m writing a book on tessellations, which means making lots of figures. These illustrate the Laves tessellations, along with the Archimedeans to which they're dual. They’re also known as the Catalan tessellations in analogy to the Catalan solids, dual to the Archimedean solids.

RobFathauerArt's tweet image. I’m writing a book on tessellations, which means making lots of figures. These illustrate the Laves tessellations, along with the Archimedeans to which they're dual. They’re also known as the Catalan tessellations in analogy to the Catalan solids, dual to the Archimedean solids.
RobFathauerArt's tweet image. I’m writing a book on tessellations, which means making lots of figures. These illustrate the Laves tessellations, along with the Archimedeans to which they're dual. They’re also known as the Catalan tessellations in analogy to the Catalan solids, dual to the Archimedean solids.

Geometry Fact reposted

My latest Mathematical Enchantment explains the ins and outs of magic portals between worlds. If you find one that's knotted, be careful how you enter it: your choice could determine which alternate world you end up in! mathenchant.wordpress.com/2018/08/16/kno…

JimPropp's tweet image. My latest Mathematical Enchantment explains the ins and outs of magic portals between worlds. If you find one that's knotted, be careful how you enter it: your choice could determine which alternate world you end up in! mathenchant.wordpress.com/2018/08/16/kno…

Geometry Fact reposted

'Old Macdonald had a form; e_i /\ e_i = 0.' -- Mike Stay


Geometry Fact reposted

The geekiest calculator you'll see today: homotopy groups of spheres johndcook.com/sphere_homotop…


Geometry Fact reposted

You could describe the motion of a knight by saying it can move a distance of sqrt(5) in any direction.

AlgebraFact's tweet image. You could describe the motion of a knight by saying it can move a distance of sqrt(5) in any direction.

Geometry Fact reposted

The Koch Star. Fractal Dimension = log-base-phi of 2 ≈ 1.44

CmonMattTHINK's tweet image. The Koch Star. Fractal Dimension = log-base-phi of 2 ≈ 1.44

Geometry Fact reposted

"Crochet Topology" by Moira Chas, this month's Feature Column. Chas uses crochet to explore and understand map-coloring on surfaces bit.ly/2FzVIs8

amermathsoc's tweet image. "Crochet Topology" by Moira Chas, this month's Feature Column. Chas uses crochet to explore and understand map-coloring on surfaces bit.ly/2FzVIs8

Geometry Fact reposted

Crocheting Adventures with Hyperbolic Planes: Tactile Mathematics, Art and Craft for all to Explore. Magnificent! crcpress.com/Crocheting-Adv…


“For Example: On Occasion of the Fiftieth Anniversary of Grünbaum’s Convex Polytopes” Examples, images, and problems from polytope theory. ams.org/journals/notic… [pdf, 6 pages]


“Circle packings, conformal maps, and quasiconformal maps” from Terence Tao’s course notes on complex analysis terrytao.wordpress.com/2018/04/12/246…


Progress on the Hadwiger–Nelson problem, to determine the minimum number of colors required to color every point of the plane in such a way that any 2 points at distance 1 have different colors: en.wikipedia.org/wiki/Hadwiger%…

The chromatic number of the plane is at least 5. arxiv.org/abs/1804.02385



Geometry Fact reposted

A generic 2D slice through the centre of an icosahedron is an irregular decagon. A generic 3D slice through the centre of a 4D 600-cell is an irregular polyhedron with 218 faces (152 triangles, 66 quadrangles). Slice all the regular 4D polytopes here: gregegan.net/APPLETS/27/27.…


Handouts for a summer workshop led in 1991 by John Conway, Peter Doyle, Jane Gilman, and Bill Thurston.

Geometry and the Imagination in Minneapolis. arxiv.org/abs/1804.03055



Geometry Fact reposted

I wrote a twitter bot that generates 2-dimensional tilings with randomized parameters. It will auto-tweet once a day, though it may occasionally be more chatty when I'm having fun extending it. I hope you enjoy!

#Hyperbolic #tiling with {7,3} #symmetry. Mirrors 0,1 are active.

TilingBot's tweet image. #Hyperbolic #tiling with {7,3} #symmetry. Mirrors 0,1 are active.


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