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Recently, I learned that in addition to the regular skew polyhedra that are
infinite (Melinda's IRPs), there are regular skew polyhedra which are
finite. They close back around on themselves in 4 dimensions. Here was an
awesome opportunity to make MagicTile genuinely applicable to the 4D_Cubing
group :D
To start, I've included 4D skew polyhedra associated with some duoprisms,
the runcinated 5-cell, and the bitruncated 5-cell, though there are additional
possibilities
the future. These should be pleasant to solve in skew mode, and I'm sure
many interesting observations can be made of the shapes included so far.
For instance, check out how the surface of the {4,6|3} relates to 3
intersecting spheres.
I just uploaded some
pics
- {4,4|4} duoprism, aka hypercube
- {4,4|5} duoprism
- {4,4|7} duoprism
- {4,6|3} runcinated 5-cell
- {6,4|3} bitruncated 5-cell
Although the duoprisms are easily seen as having genus 1, can you figure
out the genus of the other two? Not trivial to figure out by sight! I
won't give away the answer, but will say both have the same genus.
I changed the 4D viewing controls slightly from MC4D, so that the 4D camera
distance could be altered with the mouse (I didn't want to rely on a
slider). Things will mostly be familiar though, and details are in the
Help menu.
This feels like a great plateau, so now I'm going to take a break from
MagicTile for real :)
Enjoy!
Roice
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t are infinite (Melinda's IRPs), there are regular skew polyhedra which=
are finite.=A0 They close back around on themselves in 4 dimensions.=A0 He=
re was=A0an awesome opportunity=A0to make MagicTile genuinely applicable to=
the 4D_Cubing group :D=A0
with some=A0duoprisms, the runcinated 5-cell, and the bitruncated 5-cell, =
though there are edron" target=3D"_blank">additional possibilities for the future.=A0=A0=
These should be pleasant to solve in skew mode, and I'm sure many inter=
esting observations can be made of the shapes included so far.=A0 For insta=
nce, check out how the surface of the {4,6|3}=A0relates to 3 intersecting s=
pheres.=A0
=A0
I just uploaded=A0/photos/album/597055459/pic/list">some pics of...
<=
duoprism, aka hypercube
li>
div>Although the duoprisms are easily seen as having genus 1, can you figur=
e out the genus of the other two?=A0 Not trivial to figure out by sight! =
=A0I won't give away the answer, but will say both have the same genus.=
so that=A0the 4D camera distance=A0could be altered with the mouse (I didn&=
#39;t want to rely=A0on a slider).=A0 Things will mostly be familiar though=
, and details are in the Help menu.=A0
take a break from MagicTile for real :)
tation3d.com/magictile/downloads/MagicTile_v2.zip" target=3D"_blank">Enjoy!=
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Awesome !!!
I like the new forms.
Question:=20
example { 4 4|4 }
Is this 3D or 4D. I see only 4 cells.
If 4D: are there hidden cells (as in tesseract the exterior 8th cell)?
Kind regards
Ed
----- Original Message -----=20
From: Roice Nelson=20
To: 4D_Cubing@yahoogroups.com=20
Sent: Sunday, March 04, 2012 5:17 PM
Subject: [MC4D] 4D-interactive puzzles in MagicTile
=20=20=20=20
Recently, I learned that in addition to the regular skew polyhedra that a=
re infinite (Melinda's IRPs), there are regular skew polyhedra which are fi=
nite. They close back around on themselves in 4 dimensions. Here was an a=
wesome opportunity to make MagicTile genuinely applicable to the 4D_Cubing =
group :D=20=20
To start, I've included 4D skew polyhedra associated with some duoprisms,=
the runcinated 5-cell, and the bitruncated 5-cell, though there are additi=
onal possibilities for the future. These should be pleasant to solve in sk=
ew mode, and I'm sure many interesting observations can be made of the shap=
es included so far. For instance, check out how the surface of the {4,6|3}=
relates to 3 intersecting spheres.=20
=20=20=20
I just uploaded some pics of...
a.. {4,4|4} duoprism, aka hypercube
b.. {4,4|5} duoprism
c.. {4,4|7} duoprism=20
d.. {4,6|3} runcinated 5-cell
e.. {6,4|3} bitruncated 5-cell
Although the duoprisms are easily seen as having genus 1, can you figure =
out the genus of the other two? Not trivial to figure out by sight! I won=
't give away the answer, but will say both have the same genus.
I changed the 4D viewing controls slightly from MC4D, so that the 4D came=
ra distance could be altered with the mouse (I didn't want to rely on a sli=
der). Things will mostly be familiar though, and details are in the Help m=
enu.=20=20
This feels like a great plateau, so now I'm going to take a break from Ma=
gicTile for real :)
Enjoy!
Roice=20
=20=20
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Hi Ed,
It is 4D, in that the puzzle only fits together in a truly regular way in 4
dimensions. But the puzzle faces are still 2D (the {4,4|4} has 16 2D
faces). This is unlike MC4D, which has 3D faces fitting together in 4D.
Still, you can see how some of the square faces of the {4,4|4} are being
warped due to the 4D -> 3D projection. As in MC4D, shift+left drag to do
some 4D rotations that will affect this warping.
None of the 16 faces are getting hidden. Whereas in MC4D, a 3D face can be
"back facing" or "front facing" relative to a 4D camera, these 2D faces
have no such orientation. How come? Use dimensional analogy to think of a
set of 1D edges embedded in 3D. Although a 2D polygon can be back facing
or front facing in 3D (relative to a 3D camera), a 1D segment can not - a
polygon will have a normal that can only point in two directions, but a
segment has an infinite number of normal directions. Similarly for a 2D
polygon living in 4-space. Hope that made sense, but in short, there is
not a way to hide the 2D puzzle faces based on their location in 4D.
However, I should mention that skew polyhedra divide space into two halves
(the IRPs divide 3D space in two, the 4D skews divide the hypersphere
surface into two 3D partitions). It is therefore possible to consider one
of these halves the "inside" and the other the "outside". If we then
interpreted the puzzle as a solid 3D object which was the inside half, we
could hide faces based on that. I chose not to do this though, in keeping
with the MagicTile abstraction of representing puzzles as 2D surfaces
alone. In MagicTile, the Rubik's Cube is not a solid cube, only a tiling
of squares on a 2D surface.
Hope this helps clarify some.
All the best,
Roice
On Sun, Mar 4, 2012 at 2:20 PM, Eduard Baumann
> **
>
>
> Awesome !!!
>
> I like the new forms.
>
> Question:
> example { 4 4|4 }
> Is this 3D or 4D. I see only 4 cells.
> If 4D: are there hidden cells (as in tesseract the exterior 8th cell)?
>
> Kind regards
> Ed
>
>
>
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Hi Ed,
n a truly regular way in 4 dimensions. =A0But the puzzle faces are still 2D=
(the=A0{4,4|4} has=A016 2D faces). =A0This is unlike MC4D, which has 3D fa=
ces fitting together in 4D. =A0Still, you can see how some of the square fa=
ces of the {4,4|4} are being warped due to the 4D -> 3D projection. =A0A=
s in MC4D, shift+left drag to do some 4D rotations that will affect this wa=
rping.
MC4D, a 3D face can be "back facing" or "front facing" =
relative to a 4D camera, these 2D faces have no such orientation. =A0How co=
me? =A0Use dimensional analogy to think of a set of 1D edges embedded in 3D=
. =A0Although a 2D polygon can be back facing or front facing in 3D (relati=
ve to a 3D camera), a 1D segment can not - a polygon will have a normal tha=
t can only point in two directions, but a segment has an infinite number of=
normal directions. =A0Similarly for a 2D polygon living in 4-space. =A0Hop=
e that made sense, but in short, there is not a way to hide the 2D puzzle f=
aces based on their location in 4D. =A0
ace into two halves (the IRPs divide 3D space in two, the 4D skews divide t=
he hypersphere surface into two 3D partitions). =A0It is therefore possible=
to consider one of these halves the "inside" and the other the &=
quot;outside". =A0If we then interpreted the puzzle as a solid 3D obje=
ct which was the inside half, we could hide faces based on that. =A0I chose=
not to do this though, in keeping with the MagicTile abstraction of repres=
enting puzzles as 2D surfaces alone. =A0In MagicTile, the Rubik's Cube =
is not a solid cube, only a tiling of squares on a 2D surface.
All the best,
> wrote:
x #ccc solid;padding-left:1ex">
=20=20=20=20=20=20=20=20
e=20
exterior 8th cell)?
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Thanks Roice.
An other point:
in http://www.superliminal.com/cube/halloffame.htm
there is a link to my home page (clicking my name). Please change this link=
as follows.
The old adress is
http://private.mcnet.ch/baumann/
and is valable only to end juin 2012
Please change the link to=20
http://www.baumanneduard.ch/
Kind regards
Ed
----- Original Message -----=20
From: Roice Nelson=20
To: 4D_Cubing@yahoogroups.com=20
Sent: Monday, March 05, 2012 7:24 AM
Subject: Re: [MC4D] 4D-interactive puzzles in MagicTile
=20=20=20=20
Hi Ed,
It is 4D, in that the puzzle only fits together in a truly regular way in=
4 dimensions. But the puzzle faces are still 2D (the {4,4|4} has 16 2D fa=
ces). This is unlike MC4D, which has 3D faces fitting together in 4D. Sti=
ll, you can see how some of the square faces of the {4,4|4} are being warpe=
d due to the 4D -> 3D projection. As in MC4D, shift+left drag to do some 4=
D rotations that will affect this warping.
None of the 16 faces are getting hidden. Whereas in MC4D, a 3D face can =
be "back facing" or "front facing" relative to a 4D camera, these 2D faces =
have no such orientation. How come? Use dimensional analogy to think of a=
set of 1D edges embedded in 3D. Although a 2D polygon can be back facing =
or front facing in 3D (relative to a 3D camera), a 1D segment can not - a p=
olygon will have a normal that can only point in two directions, but a segm=
ent has an infinite number of normal directions. Similarly for a 2D polygo=
n living in 4-space. Hope that made sense, but in short, there is not a wa=
y to hide the 2D puzzle faces based on their location in 4D.=20=20
However, I should mention that skew polyhedra divide space into two halve=
s (the IRPs divide 3D space in two, the 4D skews divide the hypersphere sur=
face into two 3D partitions). It is therefore possible to consider one of =
these halves the "inside" and the other the "outside". If we then interpre=
ted the puzzle as a solid 3D object which was the inside half, we could hid=
e faces based on that. I chose not to do this though, in keeping with the =
MagicTile abstraction of representing puzzles as 2D surfaces alone. In Mag=
icTile, the Rubik's Cube is not a solid cube, only a tiling of squares on a=
2D surface.
Hope this helps clarify some.
All the best,
Roice
On Sun, Mar 4, 2012 at 2:20 PM, Eduard Baumann
Awesome !!!
I like the new forms.
Question:=20
example { 4 4|4 }
Is this 3D or 4D. I see only 4 cells.
If 4D: are there hidden cells (as in tesseract the exterior 8th cell)?
Kind regards
Ed
=20=20
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>
minal.com/cube/halloffame.htm
my name).=20
Please change this link as follows.
style=3D"BORDER-LEFT: #000000 2px solid; PADDING-LEFT: 5px; PADDING-RIGHT: =
0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px">
style=3D"FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color: black">Fro=
m:=20
Roice Nelson=
=20
Hi Ed,
=
IV>
Awesome !!!
I like the new forms.
Question:
example { 4 4|4 }
Is this 3D or 4D. I see only 4 cells.IV>
If 4D: are there hidden cells (as in tesseract =
the=20
exterior 8th cell)?
Kind regards
Ed
Roice,
New puzzles are beautiful! It's very nice to see these sceletons of our f=
amiliar 4D bodies and wander around them :)
I solved only one puzzle so far - bitruncated simplex (my favorite polyto=
pe :) ) in F:0:0:1 slicing. It was not very easy, and one of main problems =
is that twising rotation depends on side of face that you click: if you see=
one side, face twists clockwise, but if you go to the other side and make =
the same click, it twists counterclockwise. I think that it's not difficult=
to fix.
This puzzle has a kind of "global non-orientability": if you have wrong o=
riented edge, you can't reorient it by moving around the vertex, you have t=
o make a loop around a tube. I guess that same effects will be in 5x5 and 7=
x7 duoprisms (that are actually just another implementations of planar tori=
:) )
Thank you for these puzzles!
Andrey
=20=20
--- In 4D_Cubing@yahoogroups.com, Roice Nelson
>
> Recently, I learned that in addition to the regular skew polyhedra that a=
re
> infinite (Melinda's IRPs), there are regular skew polyhedra which are
> finite. They close back around on themselves in 4 dimensions. Here was =
an
> awesome opportunity to make MagicTile genuinely applicable to the 4D_Cubi=
ng
> group :D
>=20
> To start, I've included 4D skew polyhedra associated with some duoprisms,
> the runcinated 5-cell, and the bitruncated 5-cell, though there are addit=
ional
> possibilities
> the future. These should be pleasant to solve in skew mode, and I'm sure
> many interesting observations can be made of the shapes included so far.
> For instance, check out how the surface of the {4,6|3} relates to 3
> intersecting spheres.
>=20
> I just uploaded some
> pics
>=20
> - {4,4|4} duoprism, aka hypercube
> - {4,4|5} duoprism
> - {4,4|7} duoprism
> - {4,6|3} runcinated 5-cell
> - {6,4|3} bitruncated 5-cell
>=20
> Although the duoprisms are easily seen as having genus 1, can you figure
> out the genus of the other two? Not trivial to figure out by sight! I
> won't give away the answer, but will say both have the same genus.
>=20
> I changed the 4D viewing controls slightly from MC4D, so that the 4D came=
ra
> distance could be altered with the mouse (I didn't want to rely on a
> slider). Things will mostly be familiar though, and details are in the
> Help menu.
>=20
> This feels like a great plateau, so now I'm going to take a break from
> MagicTile for real :)
>=20
> Enjoy!
> Roice
>
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Thanks for your thoughts and positive feedback Andrey :)
That's a really cool observation about edge orientation behavior!
Also, about the duoprisms being planar tori, I wanted to mention that the
skew polyhedra are only a different view of the traditional puzzles in
MagicTile. For the duoprisms, you can switch to the {4,4} planar tori view
by setting the option "Show as Skew" to false. Changing this setting for
the bitruncated simplex will show its associated hyperbolic tiling too.
About the twisting direction relationship to the side you click on, I bet
it can be changed without too much effort like you say, so I will plan to
do this relatively soon.
aside: I did mentally debate whether the current behavior was ok or not,
and the same thing happens on all of the IRP puzzles as well. Besides
easier coding, one advantage is that it gives a visual clue of the two
different halves the skew polyhedra divide space into. A similar sort of
thing came up before with non-orientable tilings of the plane - mirrored
faces were twisting in an opposite sense. That had advantage (visual clues
to the topology), but the same disadvantage of making solving difficult. We
settled on making all faces always twist CCW when left-clicked, and it
sounds like I should take the same path here. I would like to make solving
as pleasant as possible for the skews.
Cheers,
Roice
On Tue, Mar 6, 2012 at 10:03 AM, Andrey
> Roice,
> New puzzles are beautiful! It's very nice to see these sceletons of our
> familiar 4D bodies and wander around them :)
> I solved only one puzzle so far - bitruncated simplex (my favorite
> polytope :) ) in F:0:0:1 slicing. It was not very easy, and one of main
> problems is that twising rotation depends on side of face that you click:
> if you see one side, face twists clockwise, but if you go to the other side
> and make the same click, it twists counterclockwise. I think that it's not
> difficult to fix.
> This puzzle has a kind of "global non-orientability": if you have wrong
> oriented edge, you can't reorient it by moving around the vertex, you have
> to make a loop around a tube. I guess that same effects will be in 5x5 and
> 7x7 duoprisms (that are actually just another implementations of planar
> tori :) )
>
> Thank you for these puzzles!
>
> Andrey
>
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havior!=A0 Also,=A0about the duoprisms=A0being planar tori, I wanted to men=
tion that the skew polyhedra are only a different view of the traditional p=
uzzles in MagicTile.=A0 For the duoprisms, you can switch to the {4,4}=A0pl=
anar tori=A0view by setting the option "Show as Skew" to false.=
=A0=A0Changing this=A0setting for the bitruncated simplex will show its ass=
ociated hyperbolic tiling too.
u click on, I bet it can be changed without too much effort like you say, s=
o I will plan to do this relatively soon.
I did mentally debate whether the current behavior was ok or not, and the =
same thing happens on all of the IRP puzzles as well.=A0 Besides easier cod=
ing, one advantage is that it gives a visual clue of the two different halv=
es the skew polyhedra divide space into.=A0 A similar sort of thing came up=
before with non-orientable tilings of the plane - mirrored faces were twis=
ting in an opposite sense. That had advantage (visual clues to the topolog=
y), but the same disadvantage of making solving difficult. We settled on m=
aking all faces always twist CCW when left-clicked, and it sounds like I sh=
ould take the same path here.=A0 I would like to make solving as pleasant a=
s possible for the skews.=A0
color:rgb(204,204,204);border-left-width:1px;border-left-style:solid" class=
=3D"gmail_quote">Roice,
=A0New puzzles are beautiful! It's very nice to see these sceletons of=
our familiar 4D bodies and wander around them :)
=A0I solved only one puzzle so far - bitruncated simplex (my favorite poly=
tope :) ) in F:0:0:1 slicing. It was not very easy, and one of main problem=
s is that twising rotation depends on side of face that you click: if you s=
ee one side, face twists clockwise, but if you go to the other side and mak=
e the same click, it twists counterclockwise. I think that it's not dif=
ficult to fix.
=A0This puzzle has a kind of "global non-orientability": if you =
have wrong oriented edge, you can't reorient it by moving around the ve=
rtex, you have to make a loop around a tube. I guess that same effects will=
be in 5x5 and 7x7 duoprisms (that are actually just another implementation=
s of planar tori :) )
=A0Thank you for these puzzles!
=A0Andrey
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Hi Andrey,
I went ahead and made your suggested change this evening. So skew puzzles
will twist CCW on a left click regardless of the side you click. It feels
like a definite improvement for both the IRPs and the 4D skew polyhedra, so
thanks again for suggesting that... link to
download
seeya,
Roice
On Tue, Mar 6, 2012 at 10:03 AM, Andrey
> Roice,
> New puzzles are beautiful! It's very nice to see these sceletons of our
> familiar 4D bodies and wander around them :)
> I solved only one puzzle so far - bitruncated simplex (my favorite
> polytope :) ) in F:0:0:1 slicing. It was not very easy, and one of main
> problems is that twising rotation depends on side of face that you click:
> if you see one side, face twists clockwise, but if you go to the other side
> and make the same click, it twists counterclockwise. I think that it's not
> difficult to fix.
> This puzzle has a kind of "global non-orientability": if you have wrong
> oriented edge, you can't reorient it by moving around the vertex, you have
> to make a loop around a tube. I guess that same effects will be in 5x5 and
> 7x7 duoprisms (that are actually just another implementations of planar
> tori :) )
>
> Thank you for these puzzles!
>
> Andrey
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Hi Andrey,
his evening. =A0So skew puzzles will twist CCW on a left click regardless o=
f the side you click. =A0It feels like a definite improvement for both the =
IRPs and the 4D skew polyhedra, so thanks again for suggesting that...=A0 href=3D"http://www.gravitation3d.com/magictile/downloads/MagicTile_v2.zip"=
>link to download
<=
div class=3D"gmail_quote">On Tue, Mar 6, 2012 at 10:03 AM, Andrey =3D"ltr"><andreyastrelin@yah=
oo.com> wrote:
x #ccc solid;padding-left:1ex">Roice,
=A0New puzzles are beautiful! It's very nice to see these sceletons of=
our familiar 4D bodies and wander around them :)
=A0I solved only one puzzle so far - bitruncated simplex (my favorite poly=
tope :) ) in F:0:0:1 slicing. It was not very easy, and one of main problem=
s is that twising rotation depends on side of face that you click: if you s=
ee one side, face twists clockwise, but if you go to the other side and mak=
e the same click, it twists counterclockwise. I think that it's not dif=
ficult to fix.
=A0This puzzle has a kind of "global non-orientability": if you =
have wrong oriented edge, you can't reorient it by moving around the ve=
rtex, you have to make a loop around a tube. I guess that same effects will=
be in 5x5 and 7x7 duoprisms (that are actually just another implementation=
s of planar tori :) )
=A0Thank you for these puzzles!
=A0Andrey