Twitter is erecting two log cabins originally built during the late 1800s inside the companys San Francisco office space. Once booths are added, each of the 20-by-20-foot cabins will be used as dining areas for Twitter employees. The 19th century relics actually came to Twitter thanks to a Craigslist posting; Lundberg Design — an architecture firm that works with the company — came upon a listing from Karl Beckmann, who salvaged the cabins from ranches in Montana. When the call from Lundberg came in, Beckmann initially thought he was being taken for a ride.