(San Francisco Chronicle 1-4-09) From the outside, the three-story redwood building with the attractive gabled roof blends with its surroundings at conifer-dotted Sierra Nevada College in Incline Village. But it's not a redwood building, and the roof is not merely decorative; it contains a complex conservation system. As to the building's siding that looks like wood - it's concrete, stamped and colored. In addition to providing good insulation, it's made of recycled material as well. The concrete contains 25 percent fly ash, a by-product of coal combustion in power plants.