On Thursday, 12 April 2012 18:03:49 UTC+1, Jarle H Knudsen wrote:
http://www.flickr.com/photos/dubidubno/7071179813/

It's attached to a platform support in the photo, but I've also seen them
on bridges and viaducts. Not knowing what it's called, I can't search for

it is a contraption for capturing and releasing flows en bloc, in a more or less ordered manner – a social machine.