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|Type=[[:Category:Polyhedron|Polyhedron]]
 
|Type=[[:Category:Polyhedron|Polyhedron]]
 
|Triangles=|Squares=|Pentagons=|Rhombic=|Rods=123+63|Spheres=64|Author=--[[User:Leo Dorst|Leo Dorst]] 15:10, 14 June 2008 (UTC)[[User:L.Dorst|L.Dorst]] }}
 
|Triangles=|Squares=|Pentagons=|Rhombic=|Rods=123+63|Spheres=64|Author=--[[User:Leo Dorst|Leo Dorst]] 15:10, 14 June 2008 (UTC)[[User:L.Dorst|L.Dorst]] }}
This is a sphere-like object with a spiral running from North pole to South pole. It is a member of a family of such spiraled spheres, which can be made all the way down to an icosahedron for which <i>n=0</i>.
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This is a sphere-like object with a spiral running from North pole to South pole. It is a member of a family of such spiraled spheres, which can be made all the way down to an icosahedron.
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<br />
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<br />
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<br />
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<gallery>
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Image:Spiral_sphere_top_s.JPG|<small>Spiral sphere <br><i>n=2</i></small>
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Image:Spiral_sphere_1_top_s.jpg|<small>Small spiral sphere <br><i>n=1</i></small>
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Image:Spiral_sphere_0_top_s.jpg|<small>Tiny spiral sphere <br><i>n=0</i> (icosahedron)</small>
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</gallery>
 
{{clr}}
 
{{clr}}
   
 
== Building Instructions ==
 
== Building Instructions ==
 
To make a member of the family, make two types of triangles, of sizes <i>n</i> and <i>n+1</i>. For the one shown above, <i>n=2</i>. Make 4 of each and connect them at their extreme vertices. This gives you a roughly tetrahedral object with rectangular holes. Give it a twist so that those holes become skew parallelograms, and fill them in with another triangular grid. These are obviously curved, and the construction also slightly curves the original big triangles but this is hardly noticeable. The result is of course a Lobel frame. The illustration below has plates at the original triangles, to show the construction.
 
   
 
<gallery>
 
<gallery>
 
Image:Spiral_sphere_tiled_s.jpg|<small>Tiled view to show construction</small>
 
Image:Spiral_sphere_tiled_s.jpg|<small>Tiled view to show construction</small>
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Image:Spiral_sphere_top_s.JPG|<small>Top view to show spiral</small>
 
</gallery>
 
</gallery>
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#To make a member of the family, start with two types of triangles in the background color, of sizes <i>n</i> and <i>n+1</i>. For the one shown above, <i>n=2</i>.
Now starting from one of the valence-5 balls, start a spiral in a different color (such as glow-in-the-dark). To make that as smooth as possible, you should take care where you make the transition to the next winding; do this at the skewed parallelogram meeting the valency-5 sphere with its blunt (120 degree) angle. See the polar view below.
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#Make 4 of each and connect them at their extreme vertices. This gives you a roughly tetrahedral object with rectangular holes.
+
#Twist the tetrahedron so that those holes become skew parallelograms, and fill them in with another triangular grid. These are obviously curved, and the construction also slightly curves the original big triangles but this is hardly noticeable.
  +
#The result is of course a [[Lobel Frames|Lobel frame]]. The first illustration in this section has tiles at the original triangles, to show the basic construction.
  +
#Now starting from one of the valence-5 balls, start a spiral in a different color (such as glow-in-the-dark). To make that as smooth as possible, you should take care where you make the transition to the next winding; do this at the skewed parallelogram meeting the valency-5 sphere with its blunt (120 degree) angle. (See the top view for details.)
   
 
{{clr}}
 
{{clr}}
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</gallery>
 
</gallery>
   
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== Related Links ==
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* [[Lobel Frames]]
 
[[Category:Polyhedron]]
 
[[Category:Polyhedron]]
[[Category:Lobel frame]]
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[[Category:Deltahedron]]
[[Category: *****]]
 

Latest revision as of 08:57, September 7, 2013

Spiral sphere
Spiral sphere s
'
TypePolyhedron
Rods 123+63 × Geomag rod icon
Spheres 64 × Geomag ball icon
Author --Leo Dorst 15:10, 14 June 2008 (UTC)L.Dorst


This is a sphere-like object with a spiral running from North pole to South pole. It is a member of a family of such spiraled spheres, which can be made all the way down to an icosahedron.



Building Instructions Edit

  1. To make a member of the family, start with two types of triangles in the background color, of sizes n and n+1. For the one shown above, n=2.
  2. Make 4 of each and connect them at their extreme vertices. This gives you a roughly tetrahedral object with rectangular holes.
  3. Twist the tetrahedron so that those holes become skew parallelograms, and fill them in with another triangular grid. These are obviously curved, and the construction also slightly curves the original big triangles but this is hardly noticeable.
  4. The result is of course a Lobel frame. The first illustration in this section has tiles at the original triangles, to show the basic construction.
  5. Now starting from one of the valence-5 balls, start a spiral in a different color (such as glow-in-the-dark). To make that as smooth as possible, you should take care where you make the transition to the next winding; do this at the skewed parallelogram meeting the valency-5 sphere with its blunt (120 degree) angle. (See the top view for details.)


Different Views Edit

Related Links Edit

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