User talk:Tomruen

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Wikipedia Day Meetup on January 18[edit]

10 sharing book cover background.jpg

In the area? You are invited to the upcoming Minnesota meetup in commemoration of Wikipedia Day.

  • Place: Seward Cafe
2129 E Franklin Ave, Minneapolis, MN 55404
  • Date: Saturday, January 18, 2014
  • Time: noon

For more info and to sign up (not required), see the meetup talk page.

This invitation was sent to users who were interested in past events. If you don't want to receive future invitations, you can remove your name from the invite list.innotata 04:15, 10 January 2014 (UTC)

Long-standing mangled sentence in 4_21_polytope[edit]

The last sentence under the rectified 421 polytope section is mangled:

The vertex figure is determined by removing the red node and node the neighbor nodea.

I traced it back to when it was merged from another article, and from that article all the way to its creation, and it appears to have been mangled from the beginning, so I have no way of knowing what the original intended meaning was. Could you fix this please? Thanks!—Tetracube (talk) 18:48, 30 January 2014 (UTC)

Cleaned up. Tom Ruen (talk) 01:42, 31 January 2014 (UTC)
Thanks!—Tetracube (talk) 16:31, 31 January 2014 (UTC)

Image error[edit]

Your G(1,3) image http://en.wikipedia.org/wiki/File:Goldberg_polyhedron_3_1.png Has one miscoloured hexagon that should be green. (As well as a couple miscoloured pixels on the other side that should also be green). 204.191.92.201 (talk) 01:04, 21 February 2014 (UTC)

Thanks! I cleaned it up. Tom Ruen (talk) 01:11, 21 February 2014 (UTC)

Subgroup graphs[edit]

Hi, I've made some SVG versions of your graphs at Talk:List of spherical symmetry groups#Subgroup relations. I also fixed two links which were incorrectly colored in your icosahedral .png, for consistency. ~ Keiji (iNVERTED) (Talk) 16:55, 2 March 2014 (UTC)

Thanks for the SVG. Tom Ruen (talk) 17:25, 23 March 2014 (UTC)

list of uniform polyhedra by Schwarz triangle[edit]

cho+4{6/2}, 2(6/2.4.6), 3 2 3/2 |

[[File:Grünbaumian great dodekicosahedron with triangles.png| Hi. I found some problems with those pictures in the article – the forms with added faces (e.g. cho+4{6/2}, giddy+20{6/2}, ri+12{10/4}, etc.) aren't shown properly, because the images don't have those added faces. I'd fix it myself, but Stella appears to be easily upset by faces such as {6/2} and {10/4}, and trying to "fake" them as {3} and {5/2} results in polyhedra with three faces to an edge which Stella is also quite upset by. So, could you please help? Thanks. Double sharp (talk) 08:00, 23 March 2014 (UTC)

I also don't have any easy way to draw these correctly. Could some be marked up by hand? Tom Ruen (talk)
Hmm...after playing around with what Stella will tolerate...will this do for cho+4{6/2}? It's not perfect, but I've got trouble seeing how to make it better. Double sharp (talk) 10:48, 24 March 2014 (UTC)
(Doing this really makes me think I should get pictures ready for all these polyhedra with the absolutely correct colouring, but this might take a while.) Double sharp (talk) 10:50, 24 March 2014 (UTC)

(It appears to work properly sometimes, but not consistently. This is slightly irritating.) Double sharp (talk) 05:49, 30 March 2014 (UTC)

help with CDD diagrams?[edit]

Tidtidohi's diagram can't seem to be displayed probably with the already drawn elements: User:Double sharp/Polychora/Truncates (#32). Double sharp (talk) 14:09, 27 March 2014 (UTC)

(and the more complicated diagrams on User:Double sharp/Polychora are a complete trainwreck currently because I've been faking the diagrams) Double sharp (talk) 14:31, 27 March 2014 (UTC)
Hi DS, if you want to hand-draw what CDs you need, I can look to see what's the easiest way to implement my current system of top-middle-bottom rows. Some perhaps need to just be purely single-graphical in every markup case, like File:CDel K6 636 11.png. Tom Ruen (talk) 18:23, 28 March 2014 (UTC)
All right, I'll go through them and show you the problematic ones... Double sharp (talk) 05:27, 29 March 2014 (UTC)

I think the problem is not so much that the diagrams are impossible to be displayed or anything like that using your system. The trouble is that not all the possible node markings are supported: e.g. there's no away I can create a branch with the top node marked 4/3 and the bottom node 4 (which BTW I need for #324, iquatoc). I think they should all work, except for the odd simplicial diagram (e.g. #553, kavahto, ((x4/3(x4o)3/2x4)), where each set of parentheses denotes a simplicial loop in the diagram (for example, (s3s3s5/2) is the small snub icosicosidodecahedron): thus the loops are (x4/3x4o), making a triangle, (x4o3/2x4) making another triangle sharing the "4" side with the first triangle, and the outermost loop encloses these triangles into a tetrahedron. Those few I think I need to make myself: I'm fine with that. But I think the current system ought to be extended with all possible rational node markings involving 3/2, 4/3, 5/2, 5/3, and 5/4. Double sharp (talk) 14:24, 3 April 2014 (UTC)

do Schwarz triangles have to be spherical?[edit]

Our article on Schwarz triangle defines them as spherical triangles: but then we then mention later on in the article that "The (2 3 7) Schwarz triangle is the smallest hyperbolic Schwarz triangle, and as such is of particular interest." So can we use the name for Euclidean and hyperbolic triangles as well? (Can we just call them triangular fundamental domains?) Double sharp (talk) 16:14, 29 March 2014 (UTC)

I don't know. The article says its a generalization of Schwarz spherical triangle list. Tom Ruen (talk)

great icosahedron as faceting?[edit]

I was thinking, given the compound of two great icosahedra and retrosnub tetrahedron construction of the great icosahedron, that it should be possible to create an (irregular) great icosahedron by faceting a truncated octahedron. Is this true? (I've been trying in Stella: haven't got it yet.) Double sharp (talk) 03:21, 30 March 2014 (UTC)

Sorry, faceting never fascinated me enough to worry about it. User:Steelpillow probably knows. Tom Ruen (talk) 03:36, 30 March 2014 (UTC)
Thanks. I asked him at User talk:Steelpillow#great icosahedron as faceting?. Double sharp (talk) 04:59, 30 March 2014 (UTC)

Euclidean tilings[edit]

I collected some Wythoffian versions (for now just linear CD diagrams) at User:Double sharp/List of uniform tilings by Schwarz triangle. Star forms are given for only the Euclidean ones at the moment. Should I keep the hyperbolic tilings in here, given that they're already exhaustively documented in about the same way (Wythoff construction) on many other pages?

Pictures are a problem for the star forms, though, because of overlapping faces. (It's the same problem we get for spherical star polyhedra. There we have the option of flat-faced polyhedra: in Euclidean space we do not.) But they really should be there, just for consistency with the rest. (Maybe just colour one vertex, like I did at the picture on order-7 heptagrammic tiling?)

No plans to add the star hyperbolic tilings, BTW, as they're not well-documented at present. There are obviously an infinite number. (Some documented illustrative examples by McNeill: 3 | 7/2 3, 2 | 7/2 7, 3 | 7/3 7, 4 | 7/2 4, 4 | 5/2 4, 7/3 ∞ | 2.) Double sharp (talk) 05:42, 30 March 2014 (UTC)

P.S. maybe for tetragonal fundamental domains on hyperbolic plane (2 3 4 5) is more representative, as it's the smallest with four different numbers. This is the one Klitzing uses as an illustration. Klitzing now has a page on these in 2D and 3D. Double sharp (talk) 05:46, 30 March 2014 (UTC)

Vertex configurations of sirsid and girsid[edit]

Four and a half years late, but I think I might have figured out what the problem is: see Talk:Great retrosnub icosidodecahedron. Double sharp (talk) 06:33, 30 March 2014 (UTC)

relationships among hyperoctahedral polytopes[edit]

Hi. Bowers has a diagram showing these on his page, but doesn't explain it: do you know what the relationship is? He gives the densities as well; each

(Coxeter-Dynkin diagram shorthand: space = 2. nothing = 3. , = 3/2. ' = 4. + = 4/2. '' = 4/3. ^ = 5. * = 5/2. *' = 5/3. ^' = 5/4. n = n. x = marked node, o = unmarked node. Parentheses loop the diagram. Proper CD diagrams later.)

1D:
dyad
2D:
  square
 og    oc
Density
3 1
square
x'o
og
x''x
oc
x'x


3D:
     cube
  gocco sirco
quith cotco tic
Density
7 3 1
cube
x'oo
gocco
(o'x''x)
sirco
xo'x
quith
ox''x
cotco
(x'x''x)
tic
ox'x
4D:
              tes
       gittith    sidpith
  wavitoth skiviphado  srit
quitit thaquitoth thatoth tat
5D:
                  pent
         ginnont        scant
     fawdint  skatbacadint   span
 wavinant gikcavadint skivbadant sarn
quittin waquitant danbitot nottant tan
6D:
(later)

Double sharp (talk) 14:42, 3 April 2014 (UTC)

Sorry, stars are all mush in my brain, at least for quick thinking. Tom Ruen (talk) 01:12, 4 April 2014 (UTC)

Peak oil[edit]

You might be interested in [1]. Lot's of good analysis there. Cheers.  — TimL • talk 23:11, 7 April 2014 (UTC)

Thanks, I've read from is Gail Tverberg and the now retired The Oil Drum over many years. Tom Ruen (talk) 23:16, 7 April 2014 (UTC)

deleted

— Preceding unsigned comment added by Baumann Eduard (talkcontribs) 21:52, 8 April 2014 (UTC)

Error in picture?[edit]

I'm not sure that I have reached you. My wikipedia user page is "Baumann Eduard". Best regards Ed

I repeat my message: Dear Tomruen,

I’m talking about the following entry https://en.wikipedia.org/wiki/Conway_polyhedron_notation especially the illustration https://en.wikipedia.org/wiki/File:Conway_polyhedron_notation-examples2.png

Look at the part “gC”. I think that the red lines on top and on right side of the cube are wrong and should be the same as in part “dpC”. On top: the line left to right goes from front to back and should go from back to front. On the right side: the line bottom to top goes from back to front and should go from front to back.

Do you agree?

Kind regards Ed — Preceding unsigned comment added by Baumann Eduard (talkcontribs) 21:56, 8 April 2014 (UTC)

I see, good catch. I corrected them. Tom Ruen (talk) 22:23, 8 April 2014 (UTC)
Conway polyhedron notation-examples2.png

just wondering[edit]

would it be correct to call a runcitruncated tesseract a runcination of the tesseract? a truncation of the tesseract? because that's what the lede of runcinated tesseract seems to imply to me. (and why not runcinated tesseracts, since the article covers the runcination, runcicantellation, runcitruncation, and runcicantitruncation?) Double sharp (talk) 15:12, 9 April 2014 (UTC)

Runcination means cutting faces, and truncation is cutting corners, so runcitruncation is both, and not either alone. Yes, this article probably should be plural, and then runcinated tesseract can direct to the first section. Tom Ruen (talk) 19:29, 9 April 2014 (UTC)

Eclipses visible from the US[edit]

I was thinking about creating an article for eclipses visible from the United States, but I see you already started one at User:SockPuppetForTomruen/List of solar eclipses visible from the United States. Can you move this to main article space, or would you mind if I did? I'd like to use it as a starting point.  — TimL • talk 00:11, 10 April 2014 (UTC)

Sure, do whatever you like, move or copy, looks like its only complete for 1950-2050. Tom Ruen (talk) 00:16, 10 April 2014 (UTC)

Nets of the 64 uniform polychora[edit]

I just realized that we don't seem to have pictures for all of them, so I'm uploading them. I'm using the Bowers name to avoid collisions with already present pictures: e.g. there was already File:Grand antiprism net.png so I used the Bowers File:Pentagonal double antiprismoid net.png. The 120-cell/600-cell family really does take a lot more time than the others to load in Stella... Double sharp (talk) 07:33, 12 April 2014 (UTC)

Sounds good, although unsure why we need two Grand antiprism nets. Tom Ruen (talk) 07:41, 12 April 2014 (UTC)
(We don't really, it's just that I made one as part of a set of 64 and I didn't want to waste it. Also this one is a square image, unlike yours.) Double sharp (talk) 07:45, 12 April 2014 (UTC)
As for the Wythoffian nonuniform cases mentioned at Uniform polychoron, the easiest to do seems to be the runcic snub 24-cell (prissi, prismatorhombisnub icositetrachoron, s3s4o3x). (BTW it has a nonconvex isomorph, s3s4/3o3x.) The others aren't already present in the Stella library, so making them will be somewhat more of a challenge...but I'll think about how to do the snub tesseract and company. Do you have any ideas? :-) Double sharp (talk) 07:45, 12 April 2014 (UTC) Double sharp (talk) 07:45, 12 April 2014 (UTC)

P.S. Again for octahedral prism you already uploaded one, so I just used a slightly different name and put mine up so that I don't freak out later when I realize I haven't uploaded all 64. (Or 65, as it were, because I have a prissi net as well.) Double sharp (talk) 07:48, 12 April 2014 (UTC)

I have no ambitions towards those, except as a few minor examples as given so far. Myself I'm content to work on the hyperbolic honeycomb vertex figure images that will take quite a while. I'm glad if you can add the nets to the uniform polychora articles. Tom Ruen (talk) 07:52, 12 April 2014 (UTC)
Sure. So I will have all 64, plus 1 minor example. Double sharp (talk) 07:54, 12 April 2014 (UTC)

BTW if you're interested in another general family with only two uniform examples (like the duoantiprisms), Klitzing has this to say on the grand antiprism, which he identifies as the pentagonal member of a family of double antiprismoids:

"The general building rule for double antiprimoids would be: construct (in 4D) 2 perpendicular rings of 2n m-gonal antiprisms, respectively of 2m n-gonal antiprisms. Then connect the triangles of the one ring to the vertices of the other (and vice versa), and further more connect the lacing edges of the antiprism of one to the nearest similar edges of the other. Combinatorically all this filling stuff would be tets. But for general n,m the total figure cannot be made unit edged only. (Additionally, a single vertex orbit for sure is possible only when n=m.) Uniform exceptions occur for n=m=5 (gap) and n=m=5/3 (padiap)."

They're apparently also related to the duoantiprisms:

"Note that there is a crude mixture of gap and padiap too, which kind of is flattened somehow. In fact, gudap again uses a ring 10 paps and an orthogonal ring of 10 starps, but there the vertex set of both rings coincides. Accordingly the remaining space can be filled by 50 tets only." Double sharp (talk) 07:56, 12 April 2014 (UTC)

Good stuff! Tom Ruen (talk) 07:58, 12 April 2014 (UTC)
Padiap

Yes check.svg Done All 65 done, will be inserted into articles later. Padiap projection uploaded with short article (like your gudap article) to follow. Might consider using sidtidap, ditdidap and gidtidap as further nonconvex Wythoffian antiprismatic examples – there are only 6, and they aren't just the same old Wythoffian constructions from star polychora or facetings of such polytopes that are not really notable. Double sharp (talk) 08:19, 12 April 2014 (UTC)

Symbols, if you wanted them: sidtidap = (oo*x) s = Small ditrigonal icosidodecahedron cd.png CDel node h.png, ditdidap = (o^x*o,) s = Ditrigonal dodecadodecahedron cd.png CDel node h.png, and gidtidap = (o,o^x) s = Great ditrigonal icosidodecahedron cd.png CDel node h.png Double sharp (talk) 14:32, 12 April 2014 (UTC)
(Since there are only 4 known convex scaliforms, I uploaded the nets for them too. Possibly the duals of all of these could be done, because they are fair 4D dice – even the duals of the snub tesseract and similar nonuniform alternations.) Double sharp (talk) 14:32, 12 April 2014 (UTC)

Another nonuniform snub?[edit]

Did you try CDel node h.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node 1.pngCDel 2x.pngCDel node h.png or CDel node h.pngCDel 2x.pngCDel node h.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node 1.png? According to Klitzing it gives another scaliform polychoron (tutcup). Double sharp (talk) 13:15, 12 April 2014 (UTC)

Looks fun: [2] - 2 truncated tetrahedrons, 6 tetrahedrons, 8 triangular cupola. It could be added this this table Uniform_polychoron#Octahedral_prisms:_BC3_.C3.97_A1. Okay, I'll add it. Tom Ruen (talk) 19:09, 12 April 2014 (UTC)
p.s. I wonder about CDel node h.pngCDel 2x.pngCDel node h.pngCDel 6.pngCDel node.pngCDel 3.pngCDel node 1.png. Tom Ruen (talk) 20:59, 12 April 2014 (UTC)
CDel node h.pngCDel 2x.pngCDel node h.pngCDel 6.pngCDel node.pngCDel 3.pngCDel node 1.png CDel node h.pngCDel 2x.pngCDel node h.pngCDel 4.pngCDel node.pngCDel 4.pngCDel node 1.png
Runcic snub 263 honeycomb.png
Up and down triangular cupola and octahedra
A slice of a rectified cubic honeycomb
Runcic snub 244 honeycomb.png
Up and down square cupola and tetrahedra.
A slice of a Runcic cubic honeycomb
Still trying to get my head around these partial snubs – is the small rhombicuboctahedral prism the original polychoron that gets alternated to form tutcup? Double sharp (talk) 02:22, 13 April 2014 (UTC)
I see two approaches. You can start with CDel node 1.pngCDel 2x.pngCDel node 1.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node 1.png and do a confusing partial snub process, or start with CDel node h.pngCDel 2x.pngCDel node h.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node.png and move generator off the last mirror. I like the second approach better, example in reverse at Rhombicuboctahedron#Pyritohedral_symmetry. Tom Ruen (talk) 02:31, 13 April 2014 (UTC)
OK, so in which article should it be covered? (Because you covered the runcic snub 24-cell with its original runcitruncated 24-cell.) Double sharp (talk) 02:42, 13 April 2014 (UTC)
For now, I added to the nonuniform section of uniform polychoron, so I think that's all we can do, unless there's a citable source for scaliforms. Tom Ruen (talk) 02:47, 13 April 2014 (UTC)
OK, added as a section to rhombicuboctahedral prism as a related polychoron (as an excuse to use my net picture). That covers all 64 nonduoprismatic uniform polytopes plus the two known Wythoffian convex scaliforms. (Are there Wythoff constructions for the other two, spidrox and bidex? I think not.) Double sharp (talk) 03:52, 13 April 2014 (UTC)
Ha, added another one, CDel node h.pngCDel 2x.pngCDel node h.pngCDel 4.pngCDel node.pngCDel 4.pngCDel node 1.png Tom Ruen (talk) 03:05, 13 April 2014 (UTC)

How about CDel node h.pngCDel infin.pngCDel node.pngCDel 2x.pngCDel node h.pngCDel 3.pngCDel node h.pngCDel 6.pngCDel node.png? Do we have that one? Double sharp (talk) 05:06, 13 April 2014 (UTC)

Gyrated_tetrahedral-octahedral_honeycomb#Construction_by_alternation
Thanks! Double sharp (talk) 05:50, 13 April 2014 (UTC)

For tetracombs, since you have a page User:Tomruen/Convex uniform tetracomb, Klitzing has these partial nonuniform snubs: CDel node h.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node 1.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node h.png, CDel node 1.pngCDel 3.pngCDel node.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node h.pngCDel 3.pngCDel node h.png, CDel node.pngCDel 3.pngCDel node 1.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node h.pngCDel 3.pngCDel node h.png, CDel node h.pngCDel 3.pngCDel node h.pngCDel 3.pngCDel node h.pngCDel 4.pngCDel node.pngCDel 3.pngCDel node 1.png, CDel node 1.pngCDel 3.pngCDel node 1.pngCDel 3.pngCDel node.pngCDel 4.pngCDel node h.pngCDel 3.pngCDel node h.png. Double sharp (talk) 11:56, 14 April 2014 (UTC)

Playing around with some polychora[edit]

Apparently rectified sidtaxhi = wavhiddix and rectified dattady = swavixady. Rectified gidtaxhi is degenerate. Double sharp (talk) 04:28, 13 April 2014 (UTC)

Uniform polyhedra[edit]

Hey, I was thinking that we should show the partial snubs too for the uniform polyhedra. Currently the uniform polyhedron article only covers convex forms and AFAIK the only article that discusses Wythoffian constructions for all the forms is my list of uniform polyhedra by Schwarz triangle. As a result we only show the convex partial snubs, and I'm thinking that I could expand one of these articles with forms like CDel node h.pngCDel 3x.pngCDel rat.pngCDel 2x.pngCDel node h.pngCDel 4.pngCDel node.png (great icosahedron) – also the generalized "holosnub" where alternated odd polygons are treated as double-covered, so that {3} alternates to give {3}, {5} to {5/2}, creating forms like compound of two icosahedra = β3β3β, compound of two snub cubes = β3β4β, compound of two snub dodecahedra = β3β5β, etc. (The use of β instead of s here is just for emphasis and is unnecessary.) This incidentally leads to more duplicate constructions, e.g. o3o5β = small ditrigonal icosidodecahedron, β3β5o = small snub icosicosidodecahedron, β3o5x = small icosicosidodecahedron, β3o5x = small dodecicosidodecahedron. Double sharp (talk) 11:16, 14 April 2014 (UTC)

Uniform tilings[edit]

I don't know if I asked before, but we're missing pictures for the Euclidean star-tilings, e.g. see User:Double sharp/List of uniform tilings by Schwarz triangle. Since colouring them traditionally results in a confusing messy blob of colours due to the overlapping geometry, what do you think I should do for these pictures? Double sharp (talk) 14:39, 14 April 2014 (UTC)

DYK for April 2014 lunar eclipse[edit]

slakrtalk / 00:45, 15 April 2014 (UTC)

Moon photo[edit]

Would the image have come out better if you used a higher ISO and a shorter exposure time? Considering how fast the eclipse was occurring, isn't three seconds too long? 166.137.176.19 (talk) 05:52, 16 April 2014 (UTC)

The 3-second exposure was with a telescope with a computer motor drive that followed the earth's motion. Tom Ruen (talk) 06:29, 16 April 2014 (UTC)

Uniform polychora labellings[edit]

In 3D we have the Wythoff symbol and vertex configuration to supplement the CD diagrams. Do such things exist in 4D, or do I just have to do what I did at User:Double sharp/List of uniform polychora by Goursat tetrahedron to label the individual columns?

P.S. using these becomes somewhat problematic once we move past linear diagrams. Double sharp (talk) 14:35, 16 April 2014 (UTC)

There are vertex figures only, Coxeter diagrams replace Wythoff symbols in general. Tom Ruen (talk) 19:23, 16 April 2014 (UTC)

cupolae[edit]

think we have enough examples in the template? Stella stops here at heptagonal: McNeill goes up to decagonal. (And me being a uniform-polytope enthusiast, they're most interesting at n = 3, 4, and 5!) Double sharp (talk) 07:31, 18 April 2014 (UTC)

also I think that if we are going to mention the nonconvex isomorphs at all for the Johnsons they should be just sections in the analogous convex forms. Double sharp (talk) 07:33, 18 April 2014 (UTC)