Just months after his Microsoft farewell, Bill Gates is quietly creating a new company — complete with high-tech office space, a cryptic name and even its own trademark. Public documents describe the new Gates entity — bgC3 LLC — as a "think tank." It's housed within a Kirkland office that the Microsoft co-founder established on his own after leaving his day-to-day executive role at the company this summer. ... However, bgC3 will also oversee Gates' personal pursuit of breakthrough ideas in science and technology. The insider said the goal isn't necessarily to create new companies, although ideas could be passed along to Microsoft, the Bill & Melinda Gates Foundation — or others — as it makes sense. ... Federal trademark filings provide more clues — describing bgC3 as a think tank, under a generic trademark classification that corresponds broadly to areas including "scientific and technological services," "industrial analysis and research," and "design and development of computer hardware and software."