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Paul Ancka
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This one is a bit long: it is constructed starting with no less than 92 regular dodecahedra glued face-to-face between themselves: 12 of those are in blue, 20 further in red and the remaining 60 in orange. Pay attention now: the centers of the blue (12) and red (20) dodecahedra are the 32 vertices of a rhombic triacontahedron (a Catalan solid dual to the Archimedean icosidodecahedron), the side of the rhombic triacontahedron is 4 times the radius of the sphere inscribed in a regular dodecahedron, that is sqrt(10 + 22/sqrt(5)). In all, the complex you are seeing is itself a great polyhedron of face vector [V= 1240, F= 864, E= 2160; genus: g= 29] (one hole per face of the said rhombic triacontahedron, that is 30 in all).
The overall symmetry of the 'animal' is Ih, that is, icosahedral complete w. horiz. reflection, the same of the regular dodecahedron & icosahedron.
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Hi Ally, good presentation but there are quite a few misleading threads ... . See prof. Keith Devlin lecture on Phi - 2. The Golden Ratio & Fibonacci Numbers: Fact versus Fiction
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Why isn't SKR the secretary of education ! Obama, where were you thinking ?
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Looking for animator(s) for a math book collaboration. Do YOU know anyone?
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Have them in circles
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Challenge problem:

f is a function defined on the whole real line which has the property that f (1 + x) = f (2 − x) for all x. Assume that the equation f(x) = 0 has 8 distinct real roots. Find the sum of these roots. 
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I hope my answer is correct. If so,
f(x+1)= f(2-x) --> f(x)= f(3-x), therefore "f" function is symmetric to the point of "3/2". The sum of each symmetric two roots is 3. There are 8 roots, so 3.4=12.

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Anat, where is Dan ... he should be in the clip too ... :) 
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Atom Builder

Assemble your own atoms from buckets of Protons, Neutrons and Electrons and see where they are on the periodic table, their charge and atomic mass.

Fun, interactive, research-based simulations of physical phenomena from the PhET™ project at the University of Colorado.

Here (expects HTML5): http://goo.gl/RykXMV

More Science simulations (HTML5): http://goo.gl/MQKpAk
Older sims (inc. non HTML5): http://phet.colorado.edu/
PhET @ Wikipedia: http://goo.gl/Pyw4Bm


Podcast on Teaching with Interactive Simulations, featuring Katherine Perkins, Director of Physics Education Technology (PhET): http://goo.gl/aNF5hA
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Have them in circles
299 people
Steve Solun's profile photo
costel lupoaie's profile photo
Dylan Reeves's profile photo
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Peter Rowlett's profile photo
carlos' schaatsplank''s profile photo
Maria Droujkova's profile photo
Steve Phelps's profile photo
Teia Petrescu's profile photo
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