Houston Business Journal : It’s fitting that Houston-based Mattress Firm’s new headquarters includes four rooms designated for napping. But the office’s pinball machines, arcade games and open-concept office space plants the retailer on a growing list of companies with creative workspaces. Atlanta-based Tvsdesign designed the interiors of Mattress Firm’s 130,000-square-foot headquarters at 10201 S. Main St. More than 400 employees moved into the space in October.