whatA huddle of penguins in a wind. Nobody coordinates, yet the huddle slowly turns and drifts downwind, and over minutes every bird, even the ones that started in the middle, takes its turn on the cold face and in the warm core.

whyEmperor penguins survive the Antarctic winter this way, and the fairness of it, every bird cycling through the warmth, is not planned by any bird. The piece shows a travelling wave made of individual decisions to get out of the wind.

howA bird loses heat where it is exposed, and much more on the side the wind hits; a sheltered bird slowly warms. A bird that gets too cold on the outside leaves the edge, walks round the huddle, and tucks in on the lee side. That is all. Birds peel off the windward face and pile onto the lee face, so the huddle moves. Cold birds shiver, walkers are chevrons, wind is the hatching. Click to set where the wind blows from.