A quick post today: I’m at the airport gate waiting to get on a plane. I sent out a tweet about this brilliant advertising application of the Pi last week, but so many of you missed it on Twitter and have emailed to tell me about it since then (including one Dr Eben Upton) that I thought it deserved a spot here. Here’s a digital billboard that responds to the wind created by an approaching train

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Blowing in the (fetid subway) wind