In a June 5 interview with Bloomberg Television, Apple CEO Tim Cook said Apple is focusing on "autonomous systems," noting that one purpose of such systems is self-driving cars and that Apple sees the work as "the mother of all AI projects" and "probably one of the most difficult AI projects" to work on. Cook said Apple is not saying from a product point of view what it will do but is being straightforward that autonomy is "a core technology" it views as very important. According to reports, Apple's ambition in the space shrunk and the company narrowed its focus to developing self-driving software, and a self-driving car, probably belonging to Apple, was recently spotted in California as a Lexus car with Velodyne sensors. Apple has invested $1 billion in China's ride-sharing service Didi Chuxing, which reportedly opened a self-driving lab in Mountain View, California.