Luca Pacioli’s (c.1445–1517) book ‘Divina proportione’ (written 1496–8, published 1509) is famous in the history of mathematical beauty, but mostly for the wrong reasons.

The term ‘divine proportion’ refers to Euclid's ‘extreme and mean ratio’, known since the late 18th century as the ‘golden ratio’: $1.61803\ldots:1$.

Pacioli's use of the term ‘divine’ **was not based upon aesthetic appreciation**.

Rather, he made a mystical identification of certain properties of the ratio with attributes of God. E.g., the incommensurability of the ratio = the indefinability and ineffability of God.

But Pacioli aesthetically admired the five regular polyhedra — the platonic solids — and the archimedean solids that he knew. In the dedication of ‘Divina proportione’ he wrote that hoped that his patron would see ‘their most sweet harmony’. He linked the aesthetic value of the solids to that of the sphere, from which he saw them as deriving. He seems to have placed special value on the ‘most noble’ dodecahedron.

In his portrait (attached), a dodecahedron sits on top of one of his books as a symbol of mathematical success. His diagram is part of the construction of the tetrahedron. A glass rhombicuboctahedron hangs behind him.

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[Each day of February, I am posting a short interesting story/image/fact/anecdote related to the aesthetics of mathematics.]

#GoldenRatio #DivineProportion #MathematicalBeauty #MathArt #polyhedron #RegularSolid #PlatonicSolid

Pure #CSS #3D demo on @codepen: polyhedra morphing sequence https://codepen.io/thebabydino/pen/abmNveW

Absolutely no magic numbers, everything computed.

See Pen description for the how behind 😼

#transform #cssTransform #polyhedron #cssTransforms #polyhedra #octahedron #tetrahedron #cube #Maths #geometry #cssVariables #code #coding #frontend #web #dev #webDev #webDevelopment

Exploding triakis octahedron (short pyramids added on top of the faces) turning into an excavated octahedron (short pyramids dug into the faces) with pure #CSS #3D - live on @codepen: https://codepen.io/thebabydino/pen/DyrNrL

#Maths #geometry #polyhedra #css3D #cssTransform #cssTransforms #coding #code #transform #frontend #cssMaths #Sass #web #dev #webDevelopment #webDev #trigonometry #polyhedron #octahedron

One of my earliest #CSS #3D demos on @codepen: how to (de)construct a dodecahedron https://codepen.io/thebabydino/pen/ALQVQe

A dodecahedron is one of the 5 regular polyhedra = made up of only identical regular polygon faces. Regular polygons have all edge lengths and vertex angles equal.

#geometry #Maths #code #coding #css3D #cssTransforms #transform #frontend #polyhedron #polyhedra #PlatonicSolid #dodecahedron #cssAnimation #web #dev #webDev #webDevelopment #trigonometry #Sass #SCSS

@scdollins Excellent, I’m now trying to visualise a construction starting from the icosahedron...

A straightforward solution from an icosahedron: add two octahedra and a tetrahedron on each face of the icosahedron to get 20 * 15 faces.

Yes, the faces of the tetrahedra and octahedra merge as rhombic face, but Hedron App @hedron counts distinct faces (the tetrahedra could be distorted to make 3 distinct faces.)

#mathematics #geometry #polyhedron #3d

@narain Still trying to find 300 faces first. Playing with Hedron App @hedron , 53 regular octahedra join to make a shape with 300 faces.

Still trying to make something better...

#mathematics #geometry #polyhedron #geodesic #tiling

@obot50549535
Apparently the compound of ten tetrahedra has 300 edges (when counted as non-intersecting).

Also, some octahedral geodesic polyhedra and Goldberg polyhedra have 300 edges: u5O and c5C at https://en.wikipedia.org/wiki/List_of_geodesic_polyhedra_and_Goldberg_polyhedra#Octahedral

Nice, but still looking for 300 faces (or vertices)...

#askfedi #mathematics #geometry #iTeachMath #polyhedron #geodesic

Do you know a polyhedron that has 300 faces? Ideally nice and non-trivial.

Or a polyhedron with 300 edges or 300 vertices?

#askfedi #mathematics #geometry #iTeachMath #polyhedron

Something newer: an elegant "almost orthogonal polyhedron: a polyhedron whose adjacent faces are orthogonal to each other, except on one edge." https://www.gathering4gardner.org/g4g15gift/ExchangeArchive-AlmostOrthogonalPolyhedra-G15-093-1.pdf

h/t @robinhouston

#geometry #polyhedron