A building of bubbles

The swim center for the Olympics, which looks like it formed out of froth, was designed using the mathematics of foam.

The NationalAquaticsCenter in Beijing, newly built for the Olympics, is a glowing cube of bubbles. The walls, roof and ceiling of the “Water Cube” are covered — indeed, made from — enormous bubbles that seem to have drifted into place randomly, as if floating on the surface of a pool.