### URLS du π Day 2014

It's the Annual Celebration. This post should show up on 3/14 at 1:59:27pm EST. (Or as close as the blog software can get it.) Once again, check out this mesmerizing animated GIF from the Pi article at Wikipedia:

(Click for the big version and a whole bunch of WikiLegalese.)

• Steve Landsburg has some neat formulas for calculating π; the historical trick to calculating it precisely is to find a series that converges quickly.

• But this from the NYT is pretty cool too.

To calculate pi, take two identical balls. Put one near a wall and roll the other ball toward it. The first ball will hit the second, which will bounce off the wall and come back to hit the first ball. Click click click. Three collisions. The first digit of pi is a three. The machine works!

Come on. But:

A first ball that’s 100 times as massive will create 31 clicks. 10,000 times as massive will create 314 clicks.

Wha!?

You have to make the standard physics assumptions of perfectly elastic ball/ball and ball/wall collisions, no friction, everything perfectly lined up. But it's a pretty neat trick anyhow.

A non-π URL: Econ blogger Tyler Cowen often presents "very good sentences" in stuff he reads. Let me present this one from him:

Technocrats who rail against the ideologies of others are often the most ideological people around, even if their biases do not line up with the political spectrum in the usual manner.

Click over for the full context. But I think I've seen Jonah Goldberg make a related point: the people who claim to be "non-ideological" pragmatists/problem-solvers/conversation-starters are usually doing so to slip in their own values and ideologies under the radar.