In the three years since Hurricane Katrina hit New Orleans, engineers, architects, artists, and designers have grappled in myriad ways with the city's central dilemma: how are its people and the Mississippi River to coexist? Some concentrate on rebuilding the levees, others on designing low-cost, storm-resistant housing. Others still say that vulnerable neighborhoods should be abandoned altogether. Kiduck Kim and Christian Stayner of the Harvard Graduate School of Design ventured further, proposing a solar-powered city of floating houses that look like sugar cubes. This would "welcome the river in," they say, rather than treating it as "an unwanted guest." Practical? Maybe not. Inspirational? Definitely.