DOUBLE BUBBLE: During a calm stretch between rapids on a river kayaking trip a few years ago, UC Davis mathematician Joel Hass and Real Software owner Roger Schlafly of Santa Cruz figured out a way to solve a 2,000-year-old problem: What is the most efficient shape enclosing two volumes? A double bubble is the answer, according to a computer program they wrote to analyze the problem, introducing new computational techniques into theoretical mathematics in the process. Jim Hoffman, a graphics programmer at the Mathematical Sciences Research Institute in Berkeley assisted in transforming the data into three-dimensional graphics. This "torus" bubble efficiently encloses two unequal volumes.