After Katrina, blue tarpaulins fluttered in the breeze, trying to protect what little was left. In some places, the cheap tarp was the most expensive thing on the property. In Houston, salvation came in the form of white sheets, white t-shirts, white bandanas, white garbage bags — anything that could be tied to a car antenna, a windowsill, a rooftop, a branch. A sign of life. A sign of resignation. A sign of surrender.