It’s an open secret that Apple is working on autonomous driving systems — the company seems to have even put self-driving vehicles on the road. But now Apple CEO Tim Cook has hinted that the company’s AI work is meant for more than just autonomous cars.

“[Autonomous] systems can be used in a variety of ways,” Cook said during a call with investors this afternoon. “A vehicle is only one, but there are many different areas of it. And I don’t want to go any further with that.”

“We do have a large project going.”

The answer makes it pretty clear that Apple isn’t limiting its AI work to autonomous vehicles. But beyond that, it leaves a lot to speculation. Autonomous systems could be used for drones, shipping, and all kinds of robots, from warehouse assistants, to search robots, down to the machine that disassembles iPhones.

Apple is certainly not the only company working on these things: there are already several autonomous drones, big ambitions for autonomous factory robots, and even plans for an autonomous delivery robot.

But expanding Apple’s focus beyond cars opens up a lot more possibilities for the company, since its AI could reach far more markets. Given how many companies are investing in autonomous technologies right now, that certainly seems like the right idea — even if cars still seem to be Apple’s main target.

“We are very focused on autonomous systems,” Cook said. “We do have a large project going, and are making a big investment in this. From our point of view, autonomy is sort of the mother of all AI projects.”