Saturday, September 5, 2026
Friday, September 4, 2026
Monday, December 29, 2025
Octad Art — Bricks, Cubes, Flowers
For the bricks of the title, see other posts tagged Brick Space.
For some cubes* and flowers, see below.
Combining features of the above two images, one might picture the 24
cells of the 4×6 array underlying the Curtis Miracle Octad Generator
(MOG) as each containing an eightfold cube, pictured as above with seven
of its subcubes showing and an eighth subcube hidden behind them.
The seven visible subcubes may be colored, as in the Curtis image of
the Klein map, with seven distinct colors… corresponding to the seven
edge-colors used in the Curtis-Klein map. Each of the seven visible
subcubes in a cell may also be labeled, on its visible faces, with a symbol
denoting one of the 24 points of the projective line over GF(23), just as the
faces in the Curtis-Klein map are labeled. The hidden subcube in each cell
may be regarded as also so labeled, by the MOG label of the cell's position.
There is then enough information in the array's eightfold cubes' colors and
labels to construct the seven generating permutations of M24 described by
Curtis, and the 24 array cells may be regarded as now containing 24 distinct
entities — which perhaps might be called "octoids."
Those desiring a more decorative approach may replace the 24 labeled cubes
with 24 labeled "flowers." Each flower — like the map's symmetric seven
"petals" and the central "infinity heptagon" they surround — forms an octad.
Related Illustrations . . .
* See as well posts tagged Mathieu Cube . . .
Related material —
The 56 triangles of the eightfold cube . . .
- in Aitchison's March 9, 2018, talk (slides 32-34), and
- in this journal on July 25, 2008, and later.
Image from Christmas Day 2005.
Post last revised: December 30, 2025 @ 21:30 E.S.T.
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Thursday, May 30, 2024
Religious Game
The 132 hexads in yesterday's "Small Shapes" post suggest a look at . . .
From a biography of Aviezri Fraenkel in the above
2001 issue of The Electronic Journal of Combinatorics —
"As a scientist, Aviezri is interested in,
studies, creates and is involved in mathematics.
As a religious man, Aviezri is interested in,
studies, creates and is involved in Jewish knowledge
and heritage.
In 1962, during his stay in Minneapolis, while thinking
and discussing with a friend how computers could help
to advance Judaic studies, Aviezri conceived a very
original idea based on information retrieval, which
eventually became the unique Responsa Project,
known and used by the entire Jewish world."
I do not know what I was doing on the above publication date —
May 18, 2000 — but the following note from earlier that year
seems relevant to more-recent remarks here.
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Wednesday, May 29, 2024
The Strong Law of Small Shapes*
Two examples:
The above note led to a letter from John H. Conway, which in turn
led to the following . . .
* The title refers to a well-known 1988 article by Richard K. Guy.
A shape from the date of Guy's reported death —
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Thursday, February 15, 2024
The Isotropic Die
Related material: Theodore Sturgeon's novel The Dreaming Jewels
and his story "What Dead Men Tell" . . .
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Saturday, October 21, 2023
“Proof of Concept” at The New York Times
About the author of the above —
A related questionable "proof of concept" :
Aitchison at Hiroshima in this journal — a scholar's 2018 investigation
of M24 actions on a cuboctahedon — and . . .
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Sunday, September 10, 2023
For Orson Welles and Yul Brynner
Two examples from the Wikipedia article "Archimedean solid" —
Iain Aitchison said in a 2018 talk at Hiroshima that
the Mathieu group M24 can be represented as permuting
naturally the 24 edges of the cuboctahedron.
The 24 vertices of the truncated octahedron are labeled
naturally by the 24 elements of S4 in a permutahedron —
Can M24 be represented as permuting naturally
the 24 vertices of the truncated octahedron?
Related material from the day Orson Welles and Yul Brynner died —
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Sunday, April 17, 2022
Easter for Aitchison*
* See other posts tagged Aitchison in this journal.
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Sunday, March 20, 2022
Mathieu Cube Exercise, Continued
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Saturday, February 26, 2022
Saturday, February 5, 2022
Mathieu Cube Labeling
Shown below is an illustration from "The Puzzle Layout Problem" —
- September 2003
-
Lecture Notes in Computer Science 2912:500-501
DOI:10.1007/978-3-540-24595-7_50 - Source: DBLP
-
Conference: Graph Drawing, 11th International Symposium,
GD 2003, Perugia, Italy, September 21-24, 2003, Revised Papers - Authors: Kozo Sugiyama, Seok-Hee Hong, Atsuhiko Maeda
Exercise: Using the above numerals 1 through 24
(with 23 as 0 and 24 as ∞) to represent the points
∞, 0, 1, 2, 3 … 22 of the projective line over GF(23),
reposition the labels 1 through 24 in the above illustration
so that they appropriately* illustrate the cube-parts discussed
by Iain Aitchison in his March 2018 Hiroshima slides on
cube-part permutations by the Mathieu group M24.
A note for Northrop Frye —
Interpenetration in the eightfold cube — the three midplanes —
A deeper example of interpenetration:
Aitchison has shown that the Mathieu group M24 has a natural
action on the 24 center points of the subsquares on the eightfold
cube's six faces (four such points on each of the six faces). Thus
the 759 octads of the Steiner system S(5, 8, 24) interpenetrate
on the surface of the cube.
* "Appropriately" — I.e. , so that the Aitchison cube octads correspond
exactly, via the projective-point labels, to the Curtis MOG octads.
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Monday, March 9, 2020
“Archimedes at Hiroshima” Continues.
The title is from a post of January 10, 2019.
A figure from this journal on June 1, 2019 —
The following figure may help relate labelings of the
truncated octahedron ("permutahedron") to labelings
of its fellow Archimedean solid, the cuboctahedron.
See as well other posts tagged Aitchison.
[addtoany]
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The Bucharest Cross
For fans of "The Zero Theorem" —
The 24 permutations of S4 arranged on a cube
by Cristi Stoica of Bucharest at
http://www.unitaryflow.com/2009/06/polyhedra-and-groups.html:
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Wednesday, February 19, 2020
Aitchison’s Octads
The 759 octads of the Steiner system S(5,8,24) are displayed
rather neatly in the Miracle Octad Generator of R. T. Curtis.
A March 9, 2018, construction by Iain Aitchison* pictures the
759 octads on the faces of a cube , with octad elements the
24 edges of a cuboctahedron :
The Curtis octads are related to symmetries of the square.
See my webpage "Geometry of the 4×4 square" from March 2004.
Aitchison's p. 42 slide includes an illustration from that page —
Aitchison's octads are instead related to symmetries of the cube.
Note that essentially the same model as Aitchison's can be pictured
by using, instead of the 24 edges of a cuboctahedron, the 24 outer
faces of subcubes in the eightfold cube .
Image from Christmas Day 2005.
* http://www.math.sci.hiroshima-u.ac.jp/branched/files/2018/
presentations/Aitchison-Hiroshima-2-2018.pdf.
See also Aitchison in this journal.
[addtoany]
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Tuesday, December 17, 2019
Picturing Aitchison’s Mathieu Generators
Click to enlarge.
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Friday, November 29, 2019
Verifying Aitchison’s Cuboctahedral Generation of M24
Shown below are Aitchison's March 2018 M24 permutations
and their relabeling, with digits only, for MAGMA checking.
In the versions below, r g b stand for red, green, blue.
Infinity has been replaced by 7 (because a digit was needed,
and the position of the infinity symbol in the Aitchison cube
was suited to the digit 7).
(r7,r1)(b2,g4)(r3,r5)(r6,g0)
mu0= (g7,g2)(r4,b1)(g6,g3)(g5,b0)
(b7,b4)(g1,r2)(b5,b6)(b3,r0)
mu1 = (r7,r2,)(b3,g5)(r4,r6)(r0,g1)
(g7,g3)(r5,b2)(g0,g4)(g6,b1)
(b7,b5)(g2,r3)(b6,b0)(b4,r1)
mu2 = (r7,r3)(b4,g6)(r5,r0)(r1,g2)
(g7,g4)(r6,b3)(g1,g5)(g0,b2)
(b7,b6)(g3,r4)(b0,b1)(b5,r2)
mu3 = (r7,r4)(b5,g0)(r6,r1)(r2,g3)
(g7,g5)(r0,b4)(g2,g6)(g1,b3)
(b7,b0)(g4,r5)(b1,b2)(b6,r3)
mu4 = (r7,r5)(b6,g1)(r0,r2)(r3,g4)
(g7,g6)(r1,b5)(g3,g0)(g2,b4)
(b7,b1)(g5,r6)(b2,b3)(b0,r4)
mu5 = (r7,r6)(b0,g2)(r1,r3)(r4,g5)
(g7,g0)(r2,b6)(g4,g1)(g3,b5)
(b7,b2)(g6,r0)(b3,b4)(b1,r5)
mu6 = (r7,r0)(b1,g3)(r2,r4)(r5,g6)
(g7,g1)(r3,b0)(g5,g2)(g4,b6)
(b7,b3)(g0,r1)(b4,b5)(b2,r6)
Table 1 —
0 1 2 3 4 5 6 7
r 1 2 3 4 5 6 7 8
g 9 10 11 12 13 14 15 16
b 17 18 19 20 21 22 23 24
The wReplace program was used with Table 1 above
to rewrite mu0-mu6 for MAGMA.
The resulting code for MAGMA —
|
G := sub< Sym(24) |
(8,3)(20,14)(5,7)(1,10)
(8,4)(21,15)(6,1)(2,11)
(8,5)(22,9)(7,2)(3,12)
(8,6)(23,10)(1,3)(4,13)
(8,7)(17,11)(2,4)(5,14)
(8,1)(18,12)(3,5)(6,15)
G; |
The Aitchison generators passed the MAGMA test.
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Tuesday, November 26, 2019
Alea Iacta Est*
Saturday evening's post Diamond Globe suggests a review of …
Iain Aitchison on symmetric generation of M24 —
* A Greek version for the late John SImon:
«Ἀνερρίφθω κύβος».
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Sunday, November 24, 2019
Hyperbolic Memorial
From "Back to the Saddle," a post of Nov. 23, 2010 —
"A characteristic property of hyperbolic geometry
is that the angles of a triangle add to less
than a straight angle (half circle)." — Wikipedia
See as well . . .
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Saturday, November 23, 2019
Diamond Globe
An image from All Souls' Day 2010 —
This is from earlier posts tagged Permutahedron.
See also
Wallace Stevens:
A World of Transforming Shapes.
From that book (click to enlarge) —
"Before time began, there was the Cube."
— Optimus Prime.
Also from earlier posts tagged Permutahedron —
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Sunday, October 27, 2019
Friday Night Lights
Entertainment from NBC on Friday night —
The above question, and Saturday morning's post on a film director
from Melbourne, suggest an image from December's Melbourne Noir —
(March 8, 2018, was the date of death for Melbourne author Peter Temple.)
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Thursday, October 3, 2019
Apocalypse* Note
For a first look at octad.space, see that domain.
For a second look, see octad.design.
For some other versions, see Aitchison in this journal.
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Thursday, June 27, 2019
Group Actions on the 4x4x4 Cube
For affine group actions, see Ex Fano Appollinis (June 24)
and Solomon's Cube.
For one approach to Mathieu group actions on a 24-cube subset
of the 4x4x4 cube, see . . .
For a different sort of Mathieu cube, see Aitchison.
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Friday, June 21, 2019
Cube Tales for Solstice Day
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Saturday, June 1, 2019
Cuboctahedron Labeling Update
See this evening's update to the May 31 post
"Working Sketch of Aitchison’s Mathieu Cuboctahedron" —
". . . And then of course there is the obvious labeling derived from
the … permutahedron —"
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Friday, May 31, 2019
Working Sketch of Aitchison’s Mathieu Cuboctahedron
The above sketch indicates one way to apply the elements of S4
to the Aitchison cuboctahedron . It is a rough sketch illustrating a
correspondence between four edge-hexagons and four label-sets.
The labeling is not as neat as that of a permutahedron by S4
shown below, but can perhaps be improved.
Permutahedron labeled by S4 .
Update of 9 PM EDT June 1, 2019 —
. . . And then of course there is the obvious labeling derived from
the above permutahedron —
[addtoany]
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Saturday, May 4, 2019
The Chinese Jars of Shing-Tung Yau
The title refers to Calabi-Yau spaces.
Four Quartets
. . . Only by the form, the pattern,
Can words or music reach
The stillness, as a Chinese jar still
Moves perpetually in its stillness.
A less "cosmic" but still noteworthy code — The Golay code.
This resides in a 12-dimensional space over GF(2).
Related material from Plato and R. T. Curtis —
A related Calabi-Yau "Chinese jar" first described in detail in 1905 —
A figure that may or may not be related to the 4x4x4 cube that
holds the classical Chinese "cosmic code" — the I Ching —
ftp://ftp.cs.indiana.edu/pub/hanson/forSha/AK3/old/K3-pix.pdf
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Wednesday, January 16, 2019
The Dreaming Polyhedron
"Here is a recipe for preparing a copy of the Mathieu group M24.
The main ingredient is a genus-3 regular polyhedron X
with 56 triangular faces, 84 edges, and 24 vertices.
The most delicate part of this recipe is to hold the polyhedron
by the 24 vertices and immerse the rest of it in 3-dimensional space."
— "How to Make the Mathieu Group M24 ," undated webpage
by David A. Richter, Western Michigan University
Illustration from that page —
"Another model of the (universal cover of the) polyhedron X"
Related fiction —
Cover of a 1971 British paperback edition of The Dreaming Jewels,
a story by Theodore Sturgeon (first version published in 1950):
Discuss Richter's model and the Sturgeon tale
in the context of posts tagged Aitchison.
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