For Levandowski, that meant building robots. He formed a startup outside of Google named 510 Systems—a nod to the Berkeley telephone area code—and with a group of other employees began building tech that could one day prove useful to Google. That included sensors and other software specifically for self-driving cars. Unbeknownst to Google, the search giant was soon buying much of its tech for the street-mapping project from one of its own employees, Levandowski, who sold the gear via a middleman.