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Showing posts from April, 2012

Help petition the city of Austin to include funds for a planetarium in their next bond election!

Help petition the city of Austin to include funds for a planetarium in their next bond election!

More info at:
http://austinplanetarium.org/
http://www.change.org/petitions/city-of-austin-include-the-science-museum-planetarium-project-in-the-austin-2012-bond

The 120-cell encodes the symmetries of the dodecahedron.

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The 120-cell encodes the symmetries of the dodecahedron. This is probably my favorite mathematical surprise, and amazed and shocked me when I learned it (still amazes and shocks me). I always thought it'd be nice to write a blog post about this.

This week, John Baez did a lovely post about this very thing, and I learned even more about the connection by reading it.

He's been building up to that post with his #4d series. Here's a link to that series, which should hopefully filter out all the reshares you get by just searching on the hashtag.

https://plus.google.com/u/0/s/%234d%20baez

Originally shared by John Baez

So here's the climax of the #4d story, though not the end. See this 'belt' of 60 dodecahedra that makes up half the 120-cell when you curl it up into a torus? Let's understand it! It might help if you first watch the 120-cell video again.

So, what is this belt, and why is it made of 60 dodecahedra?

First: each point in a ball of radius π describes a…

Klein Bottle house / McBride Charles Ryan

Some pictures I snapped on my phone at the recent #G4G10 conference: print art, various sculptures (including a...

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Some pictures I snapped on my phone at the recent #G4G10 conference: print art, various sculptures (including a zome model and hyperbolic crochet), a 17x17x17 Rubik's Cube, a hyperbolic soccerball made of balloons, and a few more from the event at Tom Rodgers' house...