With luck, you'll be in this block-long behemoth when the Big One hits. A three-story mix of office and medical space was enlarged by placing seismic base isolators on the roof and then adding two extra stories. The rubber bearings are concealed behind a metal screen running the length of the building. The bearings form a shock-absorbing platform for the addition, while the new space acts as a large damper to steady the floors below. Architecturally, this won't grace any postcards - but it's a building that could be nowhere else.